perf(organizations): speed up filtered API lists

tests/apps/organizations/test_services.py

@@ -99,6 +99,10 @@ class OrganizationDataSnapshotRefreshServiceTest(TestCase):
             snapshot.data["industrial"][0]["certificate_number"],
             "SNAPSHOT-BATCH-CERT",
         )
+        self.assertEqual(
+            snapshot.data_source_counts,
+            [{"source": "industrial", "count": 1}],
+        )
 
     def test_refresh_for_fns_batch_matches_by_ogrn(self):
         organization = Organization.objects.create(