Do not process /sync responses for rooms the bot has just joined
Do not process /sync responses for rooms the bot has just joined

Else we can process !commands multiple times and/or process !commands from before
we were in the room (if `history_visibility` allows it).

Kona-chan/go-neb,Kona-chan/go-neb,matrix-org/go-neb,matrix-org/go-neb