Make room model mandatory on the RoomHeader (#11355)

* Remove oobData from RoomHeader

It is never used as the RoomHeader is not shown unless a Room model exists

* Make room model mandatory on the RoomHeader

src/components/structures/WaitingForThirdPartyRoomView.tsx

@@ -51,7 +51,7 @@ export const WaitingForThirdPartyRoomView: React.FC<Props> = ({ roomView, resize
         <div className="mx_RoomView mx_RoomView--local">
             <ErrorBoundary>
                 {SettingsStore.getValue("feature_new_room_decoration_ui") ? (
-                    <RoomHeader room={context.room} />
+                    <RoomHeader room={context.room!} />
                 ) : (
                     <LegacyRoomHeader
                         room={context.room}