Remove `dsync.deactivated` event

[kendallstrautman]

Description

This event is never emitted so we are officially deprecating.

Documentation

Does this require changes to the WorkOS Docs? E.g. the API Reference or code snippets need updates.

[ ] Yes

If yes, link a related docs PR and add a docs maintainer as a reviewer. Their approval is required.

No this was removed from the docs in this PR and removed from the dashboard in this PR.

[kendallstrautman]

~~We may just fully delete this since its been years since the event has been emitting. Going to check in with teams listening for this event first though.~~

Confirmed, we are going to remove it.