fix(extension-redis): unsubscribe from pubsub

[tomi-bigpi]

Fixes an issue where Redis PubSub is not unsubscribed due to delayed disconnect logic.

The Redis subscription unsubscribe code is behind a setTimeout which checks if the document instance is still available on the parent instance, which for us is never since the document is disposed by the time the setTimeout code is called.

Additionally, the existing unloadDocument call is suspect, but I left it in with a check for a valid document instance.

[janthurau]

Thank you!

[fuadsaud]

Shouldn't redis unsubscribe on afterUnloadDocument?