Remove it from request handler since there's already the context of the
request path, added through TraceLayer.

Upgrades Ruma again to make this work.

Co-authored-by: Timo Kösters <timo@koesters.xyz>

this also reverts some stateres changes

TIL body.device_id != (*body).device_id, which is pretty bad, so I
renamed body.device_id to body.sender_device

Move all state event appending to append_state_pdu.