UI: Save video settings after 'Resize output (source size)'

Fixes #4207

UI/window-basic-main.cpp

@@ -8117,6 +8117,8 @@ void OBSBasic::ResizeOutputSizeOfSource()
 	config_set_uint(basicConfig, "Video", "OutputCY", height);
 
 	ResetVideo();
+	ResetOutputs();
+	config_save_safe(basicConfig, "tmp", nullptr);
 	on_actionFitToScreen_triggered();
 }