Fix/player state

[EvieePy]

Description

Adds on_wavelink_node_disconnected and player.switch_state.
Fixes some disconnect state logic.

Has been tested on a few bots and afaik there are no issues.

Checklist

• If code changes were made then they have been tested.
  • I have updated the documentation to reflect the changes.
  • I have updated the changelog with a quick recap of my changes.
• This PR fixes an issue.
• This PR adds something new (e.g. new method or parameters).
• This PR is a breaking change (e.g. methods or parameters removed/renamed)
• This PR is not a code change (e.g. documentation, README, ...)
• I have read and agree to the Developer Certificate of Origin for this contribution

[chillymosh]

LGTM