Prevent non-admins of room from toggling class membership

lib/pangea/extensions/pangea_room_extension.dart

@@ -815,6 +815,9 @@ extension PangeaRoom on Room {
       );
       return false;
     }
+    if (room != null && !room.isRoomAdmin) {
+      return false;
+    }
     if (!pangeaCanSendEvent(EventTypes.spaceChild) && !isRoomAdmin) {
       return false;
     }

lib/pangea/widgets/class/add_space_toggles.dart

@@ -235,8 +235,13 @@ class AddToSpaceState extends State<AddToSpaceToggles> {
                     ),
                     activeColor: AppConfig.activeToggleColor,
                     value: isSuggestedInSpace(possibleParent),
-                    onChanged: (bool suggest) =>
+                    onChanged: (bool suggest) => canAdd
-                        setSuggested(suggest, possibleParent),
+                        ? setSuggested(suggest, possibleParent)
+                        : ScaffoldMessenger.of(context).showSnackBar(
+                            SnackBar(
+                              content: Text(L10n.of(context)!.noPermission),
+                            ),
+                          ),
                   )
                 : Container(),
           ),