MediaControl subscribe_get_audio_output and TVControl subscribe_get_current_channel do not work

[luskaner]

In the original code, these are always the values whenever the callback gets called:

• status: False
• payload: Unknown Error

This is because of the standard_validation checks for the key errorText that is never present as the TV returns a response like:

{"type":"response","id":"...","payload":{"soundOutput":"tv_speaker","subscribed":true}}

However, the validation works when called directly, so, it needs two validations

Edit: Same happens for TVControl subscribe_get_current_channel

[luskaner]

#95 Tries to solve this