API error from Zendesk when updating user if user doesn't exist on Zendesk

The fix here should be to bail when no remote user is found.

Whether to do a sync needs to be decided in ✨ Editing a non-synced user does not create a zendesk user Active .

> Also, $user_id is TERRIBLE name for the variable, as it's the ZENDESK ID here, not the Drupal ID which the name makes it look like.

Fixed that as a separate commit.

Automatically closed - issue fixed for 2 weeks with no activity.