Cast Integration Cleanup (#13275)

* Cast Integration Cleanup

* Fix long line

* Fixes and logging

* Fix tests

* Lint

* Report unknown state with None

* Lint

* Switch to async_add_job

Gets rid of those pesky "Setup of platform cast is taking over 10 seconds." messages.

* Re-introduce PlatformNotReady

* Add tests

* Remove unnecessary checks

* Test PlatformNotReady

* Fix async in sync context

* Blocking update

It's not using async anyway

* Upgrade pychromecast to 2.1.0

* Make reviewing easier

I like "protected" access, but I like reviewing more :)

* Make reviewing even easier :)

* Comment tests