[ws client]: unsubscribe direct when subscription is dropped. (#244)

* [ws client]: unsubscribe directly

When a subscription is dropped because of `max_notifs_per_subscription` is exceeded
the client didn't send an `unsubcribe request` until the subscription was dropped which this commit fixes.

This causes the server to still send messages to the subscription and the client would get lots of
error messages `InvalidRequestId`

* address grumbles

* fix: rephrase and not use request everywhere.