frontend: Update parent logic, remove explicit delete calls

Not necessary anymore in Windows tests at least since the parent widget
(in this case OBSBasic) is taking care of cleaning up its children.

frontend/widgets/OBSBasic.cpp

@@ -1421,8 +1421,6 @@ void OBSBasic::applicationShutdown() noexcept
 	delete deinterlaceMenu;
 	delete perSceneTransitionMenu;
 	delete shortcutFilter;
-	delete trayIcon;
-	delete trayMenu;
 	delete programOptions;
 	delete program;
 

frontend/widgets/OBSBasic_SysTray.cpp

@@ -32,7 +32,7 @@ void OBSBasic::SystemTrayInit()
 	trayIcon = new QSystemTrayIcon(QIcon::fromTheme("obs-tray", trayIconFile), this);
 	trayIcon->setToolTip("OBS Studio");
 
-	trayMenu = new QMenu;
+	trayMenu = new QMenu(this);
 
 	showHide = new QAction(QTStr("Basic.SystemTray.Show"), trayMenu);
 	sysTrayStream = new QAction(