Fix video call persisting when widget removed

src/stores/WidgetStore.ts

@@ -137,6 +137,20 @@ export default class WidgetStore extends AsyncStoreWithClient<IState> {
         if (edited && !this.roomMap.has(room.roomId)) {
             this.roomMap.set(room.roomId, roomInfo);
         }
+
+        // If a persistent widget is active, check to see if it's just been removed.
+        // If it has, it needs to destroyed otherwise unmounting the node won't kill it
+        const persistentWidgetId = ActiveWidgetStore.getPersistentWidgetId();
+        if (persistentWidgetId) {
+            if (
+                ActiveWidgetStore.getRoomId(persistentWidgetId) === room.roomId &&
+                !roomInfo.widgets.some(w => w.id === persistentWidgetId)
+            ) {
+                console.log(`Persistent widget ${persistentWidgetId} removed from room ${room.roomId}: destroying.`);
+                ActiveWidgetStore.destroyPersistentWidget(persistentWidgetId);
+            }
+        }
+
         this.emit(room.roomId);
     }