CDTOOL-1328 list version refactor

[anthony-gomez-fastly]

Change summary

Performance Optimization - Skip ListVersions API call for numeric versions

Changes to pkg/argparser/flags.go:

1. OptionalServiceVersion.Parse() - Skip API call for numeric versions
   - Added early return when user provides numeric version (e.g., --version 1)
   - Returns &fastly.Version{Number: n} directly without calling ListVersions API
   - Saves 1 API call per command when numeric version is used
   - Non-numeric versions (e.g., "latest", "active") still call API as before
2. OptionalAutoClone.Parse() - Handle unknown version state
   - Added stateUnknown check: v.Active == nil && v.Locked == nil
   - Updated autoclone condition to include stateUnknown case
   - Effect: When --autoclone is provided with numeric version, always clones (defensive behavior) since state is unknown
   - Maintains safety while benefiting from optimization

Changes to pkg/argparser/flags_test.go:

• Updated test "specific version not in list" - now expects success (version 5) instead of error
• Added explicit Active/Locked fields to "version is editable" test

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