Fix problems with read only room flag

A reload would cause the prop to not be set.

src/services/matrix.service.js

@@ -94,9 +94,18 @@ export default {
           immediate: true,
           handler(roomId) {
             this.currentRoom = this.getRoom(roomId);
-            this.currentRoomIsReadOnlyForUser = this.isReadOnlyRoomForUser(roomId, this.currentUserId);
           },
         },
+        currentRoom: {
+          immediate: true,
+          handler(room) {
+            if (room) {
+              this.currentRoomIsReadOnlyForUser = this.isReadOnlyRoomForUser(room.roomId, this.currentUserId);
+            } else {
+              this.currentRoomIsReadOnlyForUser = false;
+            }
+          }
+        }
       },
 
       methods: {