* introduce `opening` and `closing` states
Also represent them as bits so that we can easily combine them while we
are transitioning from one state to the other.
* update `open/closed` state checks
Instead of checking whether it is in one state or an other, we can check
if the current state contains some potential sub-state.
This allows us to still check if we are in the `Open` state, while also
`Closing` because the state will be `S.Open | S.Closing`.
* expose `flags` from the `useFlags` hook
* add the `Closing` and `Opening` states to the Open/Closed state
* create dedicated `abcEnabled` variables
* keep the `State.Closing` into account for `scroll locking` and `inert others`
* add a test for the `Closing` state impacting the `Dialog` component
* cleanup unused imports
* add `unmount` util to the Vue Test renderer
* update changelog
Robin Malfait
adfe121678