Fix issue in stripe_civicrm_post where a not-yet loaded contact_id, causes crash.
If you modify an entity in CiviCRM then the DAO/BAO passed into the post
hook only contains the edits; not the full record.
So, $objectRef->contact_id
may be null.
This gives a type error when it's passed into stripe_civicrm_shutdown_updatestripecustomer()
which expects an int
.
This means that sites with this extension installed will crash if any such update is made.
This PR fixes this.