🐛 [#4012] Fix content component link popup in form builder

because the WebformBuilder root was not unmounted after closing the modal, this did not work previously

src/openforms/js/components/formio_builder/WebformBuilder.js

@@ -184,6 +184,7 @@ class WebformBuilder extends WebformBuilderFormio {
         // Clean up.
         this.removeEventListener(this.dialog, 'close', dialogClose);
         this.dialog = null;
+        root.unmount();
       };
       this.addEventListener(this.dialog, 'close', dialogClose);