Don't re-render matrixchat unnecessarily
Don't re-render matrixchat unnecessarily

...on room switch. We were setting most of the state in viewRoom,
but getting the current room ID from the RoomViewStore, but this
meant we did one setState from the RoomViewStore updating,
re-rendered and then setState again in viewRoom causing another
render. This just sets the room ID in viewRoom.

matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,aperezdc/matrix-react-sdk,aperezdc/matrix-react-sdk,aperezdc/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,aperezdc/matrix-react-sdk