AutoTest: Remove unnecessary createConfigurationWidget() reimplementation

Change-Id: Iae31628b20e69e584478d9c23b7e2309d88a6922
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/autotest/testrunconfiguration.h

@@ -73,7 +73,6 @@ public:
     }
 
 private:
-    QWidget *createConfigurationWidget() override { return nullptr; }
     TestConfiguration *m_testConfig = nullptr;
 };