QmlDesigner: fix crash

Task-number: QDS-11300
Change-Id: I1fe6966445284e3e9ca5596d8f5ec866f37acc39
Reviewed-by: Mahmoud Badri <mahmoud.badri@qt.io>
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

src/plugins/qmldesigner/components/texteditor/texteditorwidget.cpp

@@ -78,6 +78,10 @@ void TextEditorWidget::setTextEditor(
         });
 
         m_textEditor->editorWidget()->installEventFilter(this);
+        // do not call the eventfilter when the m_textEditor is gone
+        connect(m_textEditor->editorWidget(), &QObject::destroyed, this, [this](QObject *) {
+            m_textEditor->editorWidget()->removeEventFilter(this);
+        });
     }
 }