asctl: Stop using DeprecatedString

Author: https://github.com/AtkinsSJ
Commit: 916e7a5a3f
Pull-request: https://github.com/SerenityOS/serenity/pull/17793
Reviewed-by: https://github.com/krkk
Reviewed-by: https://github.com/trflynn89

Userland/Utilities/asctl.cpp

@@ -30,7 +30,7 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
     auto audio_client = TRY(Audio::ConnectionToServer::try_create());
     audio_client->async_pause_playback();
 
-    DeprecatedString command = DeprecatedString::empty();
+    StringView command;
     Vector<StringView> command_arguments;
     bool human_mode = false;