Previously we assumed that a decrypted event has a room_id
but this isn't necessarily true for to_device events.
It makes sense to ignore events that aren't associated with
rooms anyway given that the list we're updating only contains
rooms!
To make sure that we handle rooms that our
client has not seen previously, we regenerate
the room list when the room is stored -
which is indicated by the js-sdk by the
Room event.
so that we can do reorderings of lists ordered by most recent event.
No optimisations here; we only update for timeline events
on live timelines that could update the "unread count".
Actually fixes vector-im/riot-web#6135 unlike #1748, which
incorrectly assumed that custom tags would be included in
listOrders.
This fix makes sure that the `default` case in the `switch`
is actually used.
