fixup! [WIP] test zgw refactor

Author: swrichards

src/open_inwoner/cms/cases/views/services.py

@@ -125,15 +125,12 @@ def get_submissions(self) -> list[SubmissionWithApiGroup]:
             for task in concurrent.futures.as_completed(futures):
                 try:
                     group_for_task = all_api_groups[futures.index(task)]
-                    subs_with_api_group.extend(
-                        [
+                    for row in task.result():
+                        subs_with_api_group.append(
                             SubmissionWithApiGroup(
                                 submission=row, api_group=group_for_task
                             )
-                            for row in task.result()
-                        ]
-                    )
-
+                        )
                 except BaseException:
                     logger.exception("Error fetching and pre-processing cases")
 
@@ -180,13 +177,10 @@ def get_cases(self) -> list[ZaakWithApiGroup]:
             ):
                 group_for_task = all_api_groups[futures.index(task)]
                 try:
-                    cases_with_api_group.extend(
-                        [
+                    for row in task.result():
+                        cases_with_api_group.append(
                             ZaakWithApiGroup(zaak=row, api_group=group_for_task)
-                            for row in task.result()
-                        ]
-                    )
-
+                        )
                 except BaseException:
                     logger.exception(
                         "Error while fetching and pre-processing cases for API group %s",