fix(whiteboard) simplify room hash generation to cover custom region shards (#15345)

react/features/whiteboard/functions.ts

     const inBreakoutRoom = isInBreakoutRoom(state);
     const roomId = getCurrentRoomId(state);
     const room = md5.hex(
-        `${locationURL?.origin}${getBackendSafePath(locationURL?.pathname)}${inBreakoutRoom ? `|${roomId}` : ''}`
+        `${getBackendSafePath(locationURL?.pathname)}${inBreakoutRoom ? `|${roomId}` : ''}`
     );
 
     return appendURLParam(collabServerBaseUrl, 'room', room);