fix(FullScreenDialog*): safer component, less memory leaks

frontend/src/components/services/FullScreenDialogServiceComponent.jsx

@@ -19,6 +19,8 @@ function FullScreenDialogServiceComponent() {
   const [children, setChildren] = useState(undefined);
   useEffect(() => {
     FullScreenDialogService.setSetChildrenComponent(setChildren);
+
+    return () => FullScreenDialogService.setSetChildrenComponent(undefined);
   }, []);
 
   const open = useMemo(() => typeof children !== "undefined", [children]);

frontend/src/services/FullScreenDialogService.js

@@ -16,11 +16,15 @@ class FullScreenDialogService {
   };
 
   closeDialog = () => {
-    this._setChildren(undefined);
+    if (typeof this._setChildren !== "undefined") {
+      this._setChildren(undefined);
+    }
   };
 
   openDialog = children => {
-    this._setChildren(children);
+    if (typeof this._setChildren !== "undefined") {
+      this._setChildren(children);
+    }
   };
 }