decklink-ui: fix double free of settings

This leads to a crash when the output is stopped, either by clicking the
stop button or when exiting OBS studio.

This crash is:
- intermittent in release builds
- reliable for me in debug builds

It is held by an `OBSData`, which, if not null, will automatically
call `obs_data_release()` on scope exit.

UI/frontend-plugins/decklink-output-ui/decklink-ui-main.cpp

@@ -68,7 +68,6 @@ void output_start()
 					   settings, NULL);
 
 		bool started = obs_output_start(output);
-		obs_data_release(settings);
 
 		main_output_running = started;