🗃️ [#3688] Remove objects config objecttype/version fields from admin

These fields are obsolete and scheduled for removal. Their values have
been copied into the respective forms where they were not set explicitly
yet.

src/openforms/registrations/contrib/objects_api/migrations/0015_alter_objectsapiconfig_objecttype_and_more.py

@@ -0,0 +1,38 @@
+# Generated by Django 4.2.11 on 2024-03-22 13:31
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        (
+            "registrations_objects_api",
+            "0014_remove_objectsapiregistrationdata_attachment_urls_and_more",
+        ),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="objectsapiconfig",
+            name="objecttype",
+            field=models.URLField(
+                blank=True,
+                editable=False,
+                help_text="Default URL of the ProductAanvraag OBJECTTYPE in the Objecttypes API. The objecttype should have the following three attributes: 1) submission_id; 2) type (the type of productaanvraag); 3) data (the submitted form data)",
+                max_length=1000,
+                verbose_name="objecttype",
+            ),
+        ),
+        migrations.AlterField(
+            model_name="objectsapiconfig",
+            name="objecttype_version",
+            field=models.IntegerField(
+                blank=True,
+                editable=False,
+                help_text="Default version of the OBJECTTYPE in the Objecttypes API",
+                null=True,
+                verbose_name="objecttype version",
+            ),
+        ),
+    ]

src/openforms/registrations/contrib/objects_api/models.py

@@ -73,12 +73,14 @@ class ObjectsAPIConfig(SingletonModel):
             "2) type (the type of productaanvraag); "
             "3) data (the submitted form data)"
         ),
+        editable=False,
     )
     objecttype_version = models.IntegerField(
         _("objecttype version"),
         null=True,
         blank=True,
         help_text=_("Default version of the OBJECTTYPE in the Objecttypes API"),
+        editable=False,
     )
     productaanvraag_type = models.CharField(
         _("Productaanvraag type"),