Properly get link for premium voice
Properly get link for premium voice

====  Tech Notes ====
Add the implemented endpoint for getting the download link for premium
voices.

forslund/mycroft-core,MycroftAI/mycroft-core,linuxipho/mycroft-core,forslund/mycroft-core,MycroftAI/mycroft-core,Dark5ide/mycroft-core,linuxipho/mycroft-core,Dark5ide/mycroft-core