Have all tag code add, modify and delete both old and new style tags

This preps us for being able to use the new data model with existing repositories

data/registry_model/registry_pre_oci_model.py

@@ -522,6 +522,7 @@ class PreOCIModel(SharedModel, RegistryDataInterface):
     try:
       tag_manifest, _ = model.tag.associate_generated_tag_manifest(namespace_name, repo_name,
                                                                    tag.name, manifest, storage_map)
+      assert tag_manifest
     except IntegrityError:
       tag_manifest = model.tag.get_tag_manifest(tag_obj)
 

data/registry_model/test/test_interface.py

@@ -13,7 +13,7 @@ from data import model
 from data.database import (TagManifestLabelMap, TagManifestToManifest, Manifest, ManifestBlob,
                            ManifestLegacyImage, ManifestLabel, TagManifest, RepositoryTag, Image,
                            TagManifestLabel, TagManifest, TagManifestLabel, DerivedStorageForImage,
-                           TorrentInfo, close_db_filter)
+                           TorrentInfo, Tag, TagToRepositoryTag, close_db_filter)
 from data.cache.impl import InMemoryDataModelCache
 from data.registry_model.registry_pre_oci_model import PreOCIModel
 from data.registry_model.datatypes import RepositoryReference
@@ -381,6 +381,8 @@ def test_get_security_status(registry_model):
 @pytest.fixture()
 def clear_rows(initialized_db):
   # Remove all new-style rows so we can backfill.
+  TagToRepositoryTag.delete().execute()
+  Tag.delete().execute()
   TagManifestLabelMap.delete().execute()
   ManifestLabel.delete().execute()
   ManifestBlob.delete().execute()