Protect against null room `topic` when updating Matrix room
Protect against null room topic
when updating Matrix room
PUT /_matrix/client/r0/rooms/!xxx%3Agitter.im/state/m.room.topic/
with { topic: null }
-> 400
: {"errcode":"M_UNKNOWN","error":"'topic' not a string type"}
Follow-up to !2313 (merged)
Part of #2609 (closed)
Edited by Eric Eastwood