Don't crash with undefined room in processBeaconEvents() (#2500)

Author: SimonBrandner

src/client.ts

@@ -8937,12 +8937,12 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
     }
 
     public processBeaconEvents(
-        room: Room,
+        room?: Room,
         events?: MatrixEvent[],
     ): void {
-        if (!events?.length) {
-            return;
-        }
+        if (!events?.length) return;
+        if (!room) return;
+
         room.currentState.processBeaconEvents(events, this);
     }