Admin Url Fix for linking from Edit/Detail to Index pages.

[nopenopenope]

Scenario:

• have two entity CRUD forms
• have some entities in Entity 1
• have a few, or none in Entity 2
• have a association or relation to Entity 2 from Entity 1, but allow it to be null and let it be null (no links existing)
• have a link to the Crud Index for Entity 2 in the Form of Entity 1 (when updating / FK existing)
• click the link

Expected result:

• you get redirected to the Index Page of the desired CRUD

Result:

• Exception, as the FK of Entity 1 does not exist in Entity 2
• and if it would, it would be the wrong one, but thats not a bug / exception

The main point is that the current setup assumes that there will always be existing links. Since non-referring pages like the Index do not need the entityId parameter, we can unset it when the scenario is matched (URL goes to Index, EntityId is set).