* fix: section being empty in flat list mode
When switching space (or removing a section later), if the Chat section
is collpased and the room list is in flat list mode in the other space,
the room list is empty.
The fix forces the section to be in expanded state if in flat list mode
* fix: store section expanded state by space
* feat: add unread status to section view
* feat: add unread tracking in room list section
* feat: populate rooms into section header vm
* test: add units for unread in section view model
* test(e2e): add unread tests
* feat: add sections to RLSV3
* feat: add sections in vms
* feat: add room list section labs flag
* fix: wrong margin for room list item when in sections
* feat: hide favourites and low priority filters
* fix: crash when changing filter
* feat: support sticky room in sections
* test: update SC snapshot
* test: update SC screenshot
* test: update RLS tests
* test: add tests to RoomListSectionHeaderViewModel
* test: fix existing test in RoomListViewModel
* test: add sections tests for RoomListViewModel
* test: add e2e tests for sections
* fix: incorrect selected room when expanding/collasping a section
* fix: typo in `roomSkipList`
* feat: use one skip list with all filters instead of one list by tag
* chore: put back comment about `roomIndexInSection`
* chore: add missing `readonly`
* chore: add doc about possible undefined value for room item vm