FIX: The `LogsNotice` service was never unsubscribing from the mbus (PR #14150)

Whenever we subscribe to something there should be an equivalent unsubscribe and this implements it for LogsNotice.

In the future we should make this closer to what Ember expects a Service to be, but at least it’s properly cleaning up after itself now.

Thanks to @markvanlan who spotted this one.

GitHub

Nice!