UI: Don't exit on unknown command line arguments

OBS Browser Source uses command line arguments for flags. Exiting on
command line arguments that are unknown to OBS prevent's that
functionality from working.

UI/obs-app.cpp

@@ -1806,12 +1806,6 @@ int main(int argc, char *argv[])
 			std::cout << "OBS Studio - " << 
 				App()->GetVersionString() << "\n";
 			exit(0);
-
-		} else {
-			std::cout << 
-				"Invalid arguments. Use --help or -h to get " << 
-				"a list of available command line arguments.\n";
-			exit(0);
 		}
 	}