feat: S2 unavailable menu item (#9657)
* add unavailable menu item to RAC and S2
* add translations
* add tests and stories
* dont propagate submenutrigger props if non unavailable
* fix test
* add docs for unavailable menu item
* fix docs lint
* fix styling and copy
* add endSlotProps so we can associate arbitrary elements with the menu item description
* shift icon down 1px
* adding alpha badge to RAC unavailable menu
* adding code mod
* fix lint and update todo copy
* period
* change to use aria-describedby via props
* pull out ContextualHelpPopover and reuse submenuTrigger
* update S2 menu tests, code mod, docs
* fix styling and slot of contextual help
* update examples, not sure why docs wont run
* fix docs and automatically move focus into the Popover if not pointer modality
this was for accessibility, ideally users should be moved into submenu/submenu dialogs unless it is hover
* forgot one todo
* review comments
* add menu strings to intl script
* remove RAC example
