Removed unsued code

As per
https://scrutinizer-ci.com/g/DeuxHuitHuit/entry_relationship_field/inspections/42ecd42a-2c07-498f-b87b-7af284a2e879/issues/files/fields/field.entry_relationship.php?status=existing&selectedSeverities%5B0%5D=10&orderField=path&order=asc