Decrypt TuyaMulticast password

[TheZ3ro]

After implementing TuyaMulticast I've forgot to include the password decryption routine.

Passwords in TuyaMulticast are AES-ECB encrypted with a static key as defined here https://github.com/ct-Open-Source/tuya-convert/blob/61ba060b8567eacd02813db431967cbe9fd23401/scripts/smartconfig/multicast.py#L14