fix(ResponsiveActions): Disable kebab when all actions are disabled

[rhamilto]

Description

Fixes #927

This PR implements the PatternFly design guideline that a kebab menu should be disabled when all of its actions are disabled.

Changes

Implementation

• Created component that uses to access state
• Kebab disabled state is now responsive to viewport width:
  • Above breakpoint: Disabled only if all regular (non-pinned) items are disabled (pinned items show as separate buttons)
  • Below breakpoint: Disabled if all items (both pinned and regular) are disabled (pinned items move into the kebab)
• Tracks disabled state separately for pinned vs regular items

Testing

• Added 5 comprehensive test cases covering all scenarios
• All 113 tests passing
• Snapshots updated

Behavior

Before

• Kebab was always enabled, even when all actions were disabled
• Poor UX: users could click the kebab to see a list of disabled actions

After

• Kebab is automatically disabled when all applicable actions are disabled
• Disabled state responds to browser resizing (pinned items moving in/out of kebab)
• Follows PatternFly accessibility guidelines

Backward Compatibility

✅ Fully backward compatible

• No changes to public API or component props
• No breaking changes
• Progressive enhancement only

Screenshots/Examples

The kebab will now properly show as disabled when appropriate, improving accessibility and UX.

Checklist

• Kebab is disabled when all dropdown actions are disabled
• Kebab disabled state responds correctly to browser resizing
• Above breakpoint: only regular items affect kebab disabled state
• Below breakpoint: both pinned and regular items affect kebab disabled state
• Fully backward compatible (no breaking changes to public API)
• Comprehensive test coverage for all scenarios
• All tests passing
• Snapshots updated

[patternfly-build]

Preview: https://react-component-groups-pr-component-groups-928.surge.sh

A11y report: https://react-component-groups-pr-component-groups-928-a11y.surge.sh

[rhamilto]

@nicolethoen, one more fix for openshift/console#16203.

This fix isn't required for openshift/console#16203 since it is not adding actions inside <ResponsiveActions> (I had to add a separate "slot" in the toolbar outside <ResonsiveActions> in order to get the desired dropdown functionality), but it will be needed long term.