test(react-menu): add hook-level regression tests for react-menu components

[mainframev]

Added unit tests to Menu components to support #36087 (should be merged first) and make sure that base hook delegation produces identical output and do not cause regression.

useMenu_unstable (19 tests)

• surfaceMotion slot exposed and configured with motion defaults derived from open
• Documented default values applied when no props are provided
• openOnHover defaults to true for submenus; explicit prop wins
• Two children → menuTrigger + menuPopover; single child → menuPopover only
• open controlled / uncontrolled / defaultOpen semantics; setOpen exposed
• triggerId is non-empty and stable across re-renders
• defaultCheckedValues honored on first render; checkedValues (controlled) wins; onCheckedValueChange fires on toggle
• isSubmenu is false at root, true inside a MenuList parent context

useMenuList_unstable (16 tests)

• components shape and root div slot; root.role = "menu"; aria-labelledby from MenuContext.triggerId
• className and aria-label spread onto root
• hasIcons / hasCheckmarks default to false and are inherited from MenuContext
• hasMenuContext flag toggles based on the surrounding MenuContext
• checkedValues controlled / uncontrolled / defaultCheckedValues semantics (folded in from the legacy useMenuList.test.ts)
• setFocusByFirstCharacter finds next item circularly and is case-insensitive
• toggleCheckbox and selectRadio work uncontrolled

useMenuPopover_unstable (20 tests)

• components shape with div root; role="presentation" always
• inline, mountNode, safeZone forwarded from MenuContext (with documented defaults)
• restoreFocusSource attributes spread onto root
• onMouseEnter: original handler still called; opens menu when openOnHover or when rendered as a submenu; no-op otherwise
• onKeyDown: original handler still called; closes menu on Escape (target inside popover, menu open, not defaultPrevented); no-op when closed or when
  prevented; closes submenu on ArrowLeft (ltr) / ArrowRight (rtl); honors MenuListContext.shouldCloseOnArrowLeft; Tab closes menu and focuses trigger
  (root) or just closes (submenu)
• Does not throw on unmount

useMenuItem_unstable (18 tests)

• components shape (root, icon, checkmark, submenuIndicator, content, secondaryContent, subText); disabled defaults to false
• persistOnClick falls back to MenuContext.persistOnItemClick when prop omitted
• root.role = "menuitem"; className / aria-label spread through
• hasSubmenu derivation: MenuTriggerContext controls the value; explicit prop wins
• submenuIndicator default chevron injection: undefined when hasSubmenu=false; defined when true; ltr vs rtl chevrons differ; user-provided
  submenuIndicator.children override the default
• icon / checkmark renderByDefault from MenuListContext: present iff hasIcons / hasCheckmarks is true (or the prop is supplied)

useMenuItemLink_unstable (9 tests)

• root overridden to "a" while inheriting all other MenuItem slots
• root.role = "menuitem"; href, className, aria-label, tabIndex spread through
• Composition with useMenuItem: inherits persistOnClick from MenuContext.persistOnItemClick, hasSubmenu from MenuTriggerContext, and disabled
  from props

useMenuItemCheckbox_unstable (11 tests)

• components shape and root/checkmark slot presence (renderByDefault: true for checkmark)
• root.role = "menuitemcheckbox"; aria-checked reflects checkedValues[name].includes(value)
• persistOnClick = true regardless of MenuContext.persistOnItemClick
• name / value exposed on state
• checkmark default-icon injection: Checkmark16Filled injected when no checkmark.children; user-provided children win

useMenuItemRadio_unstable (10 tests)

• Same shape/slot expectations as Checkbox, but root.role = "menuitemradio"
• aria-checked reflects checkedValues[name].includes(value)
• name / value exposed; Checkmark16Filled default-icon injection with user override

useMenuItemSwitch_unstable (12 tests)

• components shape includes switchIndicator: "span"; switchIndicator always present (renderByDefault: true)
• Reuses MenuItemCheckbox semantics: root.role = "menuitemcheckbox", aria-checked from checkedValues[name]
• Documented runtime quirk: a checkmark slot leaks through from the MenuItemCheckboxBase composition (it is not part of the public Switch type and
  has no default children) — pinned by a test so an unintentional change is caught
• switchIndicator default-icon injection: CircleFilled injected when no switchIndicator.children; user-provided children win

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Pull request demo site: URL

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🕵🏾‍♀️ visual changes to review in the Visual Change Report

vr-tests-react-components/Charts-DonutChart 2 screenshots

Image Name	Diff(in Pixels)	Image Type
vr-tests-react-components/Charts-DonutChart.Dynamic - Dark Mode.default.chromium.png	7530	Changed
vr-tests-react-components/Charts-DonutChart.Dynamic.default.chromium.png	5581	Changed

vr-tests-react-components/Menu Converged - submenuIndicator slotted content 2 screenshots

Image Name	Diff(in Pixels)	Image Type
vr-tests-react-components/Menu Converged - submenuIndicator slotted content.default - RTL.submenus open.chromium.png	404	Changed
vr-tests-react-components/Menu Converged - submenuIndicator slotted content.default.submenus open.chromium.png	606	Changed

vr-tests-react-components/Positioning 2 screenshots

Image Name	Diff(in Pixels)	Image Type
vr-tests-react-components/Positioning.Positioning end.updated 2 times.chromium.png	616	Changed
vr-tests-react-components/Positioning.Positioning end.chromium.png	611	Changed

vr-tests-react-components/ProgressBar converged 2 screenshots

Image Name	Diff(in Pixels)	Image Type
vr-tests-react-components/ProgressBar converged.Indeterminate + thickness - Dark Mode.default.chromium.png	67	Changed
vr-tests-react-components/ProgressBar converged.Indeterminate + thickness - High Contrast.default.chromium.png	191	Changed

vr-tests-react-components/Skeleton converged 1 screenshots

Image Name	Diff(in Pixels)	Image Type
vr-tests-react-components/Skeleton converged.Opaque Skeleton with rectangle - Dark Mode.default.chromium.png	13	Changed

vr-tests-react-components/TagPicker 3 screenshots

Image Name	Diff(in Pixels)	Image Type
vr-tests-react-components/TagPicker.disabled - High Contrast.disabled input hover.chromium.png	1319	Changed
vr-tests-react-components/TagPicker.disabled - RTL.disabled input hover.chromium.png	635	Changed
vr-tests-react-components/TagPicker.disabled.disabled input hover.chromium.png	677	Changed

There were 3 duplicate changes discarded. Check the build logs for more information.