Add persistent connection connected sensor

**Is your feature request related to a problem? Please describe.**

I'm wanting to be able to remotely manage when the Mobile App will use a Persistant connection.
For changing the persistent connection, i can use the notification command `command_persistent_connection`
However, there is no sensor that returns what the current persistant connection status is.

**Describe the solution you'd like**

It would be great to see a binary_sensor that reflects the current persistant connection state.
secondary, but not as critical, it would be good to have a Sensor that reports what the current persistant connection setting is (always, home_wifi, screen_on, never).
Perhaps it could be combined into a Select entity.

**Describe alternatives you've considered, if any**

there's not really an alternative, as i'm unable to get the state of the connection, or the current setting

**Additional context**

Furthermore, the command_persistent_connection does seem a bit flakey, and isn't as responsive as i would lik.
I can see the notification appearing in the Notification History in Companion App settings, but the persistant connection doesn't always update, or is very slow to update.