Warn in room on insufficient PL for metadata update

[Valodim]

If the bridge bot doesn't have permission in a room to e.g. change the room name or avatar, this will silently fail and the rooms desync. This situation naturally occurs in rooms created with /invite bot + !tg create, unless the creator thought to adjust the bot's PL.

I would suggest just posting a warning message to a channel if the bridge fails to set metadata. It's rarely desirable for a room to desync, and even then a notification that someone changed the room state on the telegram side shouldn't be too noisy.

(I just set up a bridge for my HS, and I gotta say I'm very very impressed! Setup went buttery smooth. Thanks for writing this, and keep up the good work!)