Remove optional migration and tests for backport

This migration is not strictly necessary for the import/export feature,
which is the focus of the v1.21.4 backport, to function. To avoid
migration conflicts now and in future, we'll remove the migration
and skip the tests that depend on them.

src/open_inwoner/openzaak/models.py

@@ -555,6 +555,12 @@ class ZaakTypeConfig(models.Model):
 
     class Meta:
         verbose_name = _("Zaaktype Configuration")
+        constraints = [
+            UniqueConstraint(
+                name="unique_identificatie_in_catalogus",
+                fields=["catalogus", "identificatie"],
+            ),
+        ]
 
     @property
     def catalogus_url(self):
@@ -610,6 +616,12 @@ class ZaakTypeInformatieObjectTypeConfig(models.Model):
 
     class Meta:
         verbose_name = _("Zaaktype Information Object Configuration")
+        constraints = [
+            UniqueConstraint(
+                name="unique_zaaktype_config_informatieobjecttype_url",
+                fields=["zaaktype_config", "informatieobjecttype_url"],
+            )
+        ]
 
     def informatieobjecttype_uuid(self):
         if self.informatieobjecttype_url:
@@ -742,6 +754,12 @@ class ZaakTypeStatusTypeConfig(models.Model):
 
     class Meta:
         verbose_name = _("Zaaktype Statustype Configuration")
+        constraints = [
+            UniqueConstraint(
+                name="unique_zaaktype_config_statustype_url",
+                fields=["zaaktype_config", "statustype_url"],
+            )
+        ]
 
     def __str__(self):
         return f"{self.zaaktype_config.identificatie} - {self.omschrijving} [{self.zaaktype_config.catalogus.base_url}]"
@@ -786,6 +804,12 @@ class ZaakTypeResultaatTypeConfig(models.Model):
 
     class Meta:
         verbose_name = _("Zaaktype Resultaattype Configuration")
+        constraints = [
+            UniqueConstraint(
+                name="unique_zaaktype_config_resultaattype_url",
+                fields=["zaaktype_config", "resultaattype_url"],
+            )
+        ]
 
     def __str__(self):
         return f"{self.zaaktype_config.identificatie} - {self.omschrijving} [{self.zaaktype_config.catalogus.base_url}]"

src/open_inwoner/openzaak/tests/test_import_export.py

@@ -1,6 +1,7 @@
 import dataclasses
 import io
 import uuid
+from unittest import skip
 
 from django.core.files.storage.memory import InMemoryStorage
 from django.test import TestCase
@@ -526,6 +527,7 @@ def test_import_jsonl_update_statustype_config_missing_zt_config(self):
         self.assertEqual(ZaakTypeStatusTypeConfig.objects.count(), 1)
         self.assertEqual(ZaakTypeResultaatTypeConfig.objects.count(), 1)
 
+    @skip("Disabled for v1.21.4 backport")
     def test_import_jsonl_update_reports_duplicate_db_records(self):
         mocks = ZGWExportImportMockData()
 
@@ -565,6 +567,7 @@ def test_import_jsonl_update_reports_duplicate_db_records(self):
         # check import
         self.assertEqual(import_result, import_expected)
 
+    @skip("Disabled for v1.21.4 backport")
     def test_import_jsonl_update_reports_duplicate_natural_keys_in_upload_file(self):
         mocks = ZGWExportImportMockData(with_dupes=True)