Sticky rooms are confusing in the room list

[ShadowJonathan]

Description

When rooms are selected for detail view, they're "frozen" in the room list, and when activity occurs on other rooms, these rooms go "around" the frozen room.

This is already a bit counter-intuitive with other chat-platforms, but the worst is is that when one clicks off of that room, the previously-frozen room now gets "sorted" "correctly", which means that room positioning is essentially complex to grasp, and very unhelpful.

Solution

Make these "chosen" rooms unfrozen in the room list, make them move when activity occurs in other rooms.

For maybe extra UX intuitiveness, scroll the sublist when the previously in-view chosen room would've been moved out-of-view, but don't do this when the room is already out-of-view (e.g. when a user is scrolling in the list to get to another room, and it gets "snapped" back when activity occurs)

For some further ideas; #16805

[MadLittleMods]

Related to #13275