UI: Only use shutdown separator upon successful close

Fixes an issue where the shutdown separator in the log file would always
appear even when the user decides not to shut down the program after
clicking close when still streaming/recording.

obs/window-basic-main.cpp

@@ -2612,8 +2612,6 @@ void OBSBasic::ClearSceneData()
 
 void OBSBasic::closeEvent(QCloseEvent *event)
 {
-	blog(LOG_INFO, SHUTDOWN_SEPARATOR);
-
 	if (outputHandler && outputHandler->Active()) {
 		SetShowing(true);
 
@@ -2631,6 +2629,8 @@ void OBSBasic::closeEvent(QCloseEvent *event)
 	if (!event->isAccepted())
 		return;
 
+	blog(LOG_INFO, SHUTDOWN_SEPARATOR);
+
 	if (updateCheckThread)
 		updateCheckThread->wait();
 	if (logUploadThread)