UI: Prevent Restream OAuth disconnection

Fix the service check for services where its name in the UI does not
match its Auth::Def service string.

In Restream's case, the service name in the UI and rtmp-services is
"Restream.io" while the service name in its Auth::Def is "Restream".
This mismatch causes the `service_check` bool to be false, whereas the
previous condition (`!!main->auth && service.find(main->auth->service())
!= std::string::npos`) would have evaluated to true.

This was broken in commit e6f1daab8c.

Fixes GitHub Issue 5290.

UI/window-basic-settings-stream.cpp

@@ -481,7 +481,8 @@ void OBSBasicSettings::on_service_currentIndexChanged(int)
 	}
 
 	auto system_auth_service = main->auth->service();
-	bool service_check = service == system_auth_service;
+	bool service_check = service.find(system_auth_service) !=
+			     std::string::npos;
 #if YOUTUBE_ENABLED
 	service_check = service_check ? service_check
 				      : IsYouTubeService(system_auth_service) &&