Issue #2150179 by swentel, larowlan: Delete confirm form for locked fields is hotlinkable.

core/modules/field/lib/Drupal/field/Entity/Field.php

core/modules/field/lib/Drupal/field/FieldInterface.php

core/modules/field_ui/field_ui.services.yml

..._ui/lib/Drupal/field_ui/Access/FieldDeleteAccessCheck.php

.../field_ui/lib/Drupal/field_ui/Routing/RouteSubscriber.php

...s/field_ui/lib/Drupal/field_ui/Tests/ManageFieldsTest.php