Step 8.5: Isolate RightPanelStore from RoomViewStore

src/stores/ReadyWatchingStore.ts

@@ -60,7 +60,13 @@ export abstract class ReadyWatchingStore extends EventEmitter implements IDestro
         // Default implementation is to do nothing.
     }
 
+    protected onDispatcherAction(payload: ActionPayload) {
+        // Default implementation is to do nothing.
+    }
+
     private onAction = async (payload: ActionPayload) => {
+        this.onDispatcherAction(payload);
+
         if (payload.action === 'MatrixActions.sync') {
             // Only set the client on the transition into the PREPARED state.
             // Everything after this is unnecessary (we only need to know once we have a client)