tab title keeps the member list after a face-to-face room is closed (#244 follow-up) #250

Follow-up to #173 / #244, found in live UI verification (main dbd1fea): on B the browser tab title stays Face-to-face · UiA1415, UiB1415 · Oct 18 11:00 — FlyBot after A left the room. The room is closed and shows Members · 1, but the title still lists both members.

Decision: the title follows the room's current name the roster gives it. A face-to-face room is named from its members when it is created, so when it has ended (closed, or someone left) the title should say so instead of listing people who are no longer in it: Face-to-face · closed — FlyBot. For a room that is still running the title is unchanged.