UI: Fix properties window size grip position on resize

To have its position updated, QDialog::resizeEvent must
be called.

obs/window-basic-properties.cpp

@@ -138,7 +138,7 @@ void OBSBasicProperties::resizeEvent(QResizeEvent *event)
 		resizeTimer = startTimer(100);
 	}
 
-	UNUSED_PARAMETER(event);
+	QDialog::resizeEvent(event);
 }
 
 void OBSBasicProperties::timerEvent(QTimerEvent *event)