Fixes bug in which clicking a song with full channels would still enter the song

* Adds function that checks if there's a free channel
* Removes full channels alert from loadChannel function
User connection now tracked so channels can be freed up when user disconnects.

* Adds check on channel when trying to switch to see if channel is free even if marked in use by checking if user has disconnected
* Adds UpdateConnectStatus to set user as connected after logging in
* Adds isConnected function to check if user is connected.