user_groups: Track acting user for bulk_add_members_to_user_group.

This is a prep-commit for populating RealmAuditLogs for changes made to
UserGroup.

Signed-off-by: Zixuan James Li <p359101898@gmail.com>

zerver/actions/user_groups.py

@@ -86,7 +86,9 @@ def update_users_in_full_members_system_group(
         remove_members_from_user_group(full_members_system_group, old_full_member_ids)
 
     if len(new_full_members) > 0:
-        bulk_add_members_to_user_group(full_members_system_group, new_full_member_ids)
+        bulk_add_members_to_user_group(
+            full_members_system_group, new_full_member_ids, acting_user=acting_user
+        )
 
 
 def promote_new_full_members() -> None:
@@ -163,7 +165,9 @@ def do_send_user_group_members_update_event(
 
 
 @transaction.atomic(savepoint=False)
-def bulk_add_members_to_user_group(user_group: UserGroup, user_profile_ids: List[int]) -> None:
+def bulk_add_members_to_user_group(
+    user_group: UserGroup, user_profile_ids: List[int], *, acting_user: Optional[UserProfile]
+) -> None:
     memberships = [
         UserGroupMembership(user_group_id=user_group.id, user_profile_id=user_id)
         for user_id in user_profile_ids

zerver/tests/test_events.py

@@ -1300,7 +1300,9 @@ class NormalActionsTest(BaseAction):
 
         # Test add members
         hamlet = self.example_user("hamlet")
-        events = self.verify_action(lambda: bulk_add_members_to_user_group(backend, [hamlet.id]))
+        events = self.verify_action(
+            lambda: bulk_add_members_to_user_group(backend, [hamlet.id], acting_user=None)
+        )
         check_user_group_add_members("events[0]", events[0])
 
         # Test remove members

zerver/views/user_groups.py

@@ -135,7 +135,7 @@ def add_members_to_group_backend(
             )
 
     user_profile_ids = [user.id for user in user_profiles]
-    bulk_add_members_to_user_group(user_group, user_profile_ids)
+    bulk_add_members_to_user_group(user_group, user_profile_ids, acting_user=user_profile)
     return json_success(request)