use DjangoValidationError when deleting tags

Author: Deepthi-Chand

api/schema/tags_schema.py

@@ -3,7 +3,11 @@
 from strawberry.types import Info
 
 from api.models import Tag
-from api.schema.base_mutation import BaseMutation, MutationResponse
+from api.schema.base_mutation import (
+    BaseMutation,
+    DjangoValidationError,
+    MutationResponse,
+)
 from api.utils.graphql_telemetry import trace_resolver
 from authorization.permissions import IsAuthenticated
 
@@ -38,6 +42,6 @@ def delete_tags(self, info: Info, tag_ids: list[str]) -> MutationResponse[bool]:
         try:
             tags = Tag.objects.filter(id__in=tag_ids)
         except Tag.DoesNotExist:
-            raise ValueError(f"Tags with IDs {tag_ids} do not exist.")
+            raise DjangoValidationError(f"Tags with IDs {tag_ids} do not exist.")
         tags.delete()
         return MutationResponse.success_response(True)