Zones do not disconnect from sources when a stream is closed

[SteveMicroNova]

Zones do not disconnect from sources when a stream is closed on the frontend. Typically this isn't an issue as when you connect a stream in the frontend it only populates with the list of sources you give it, but this is relevant for when you close a stream in the UI and a home assistant thing starts using that source and then plays to all previous zones + the new ones

In short, the solution to this is to make it so when you hit the X to close a stream it also sets all the zone source_id's to -1 while disconnecting