message_delete: Sort message_ids when sending delete_message event.

Fixes #34324.
https://chat.zulip.org/#narrow/channel/412-api-documentation/topic/Make.20message_ids.20from.20message.20update.20event.20sorted

api_docs/unmerged.d/ZF-215011.md

@@ -0,0 +1,4 @@
+* [`PATCH /messages/{message_id}`](/api/delete-message),
+  [`POST /register`](/api/register-queue), [`GET /events`](/api/get-events):
+  In `delete_message` event, all the `message_ids` will now be sorted in
+  increasing order.

zerver/actions/message_delete.py

@@ -64,7 +64,7 @@ def _process_grouped_messages_deletion(
 
     event: DeleteMessagesEvent = {
         "type": "delete_message",
-        "message_ids": message_ids,
+        "message_ids": sorted(message_ids),
     }
     if stream is None:
         assert topic is None

zerver/openapi/zulip.yaml

@@ -2136,7 +2136,10 @@ paths:
                                     Only present for clients that support the `bulk_message_deletion`
                                     [client capability][client-capabilities].
 
-                                    A list containing the IDs of the newly deleted messages.
+                                    A sorted list containing the IDs of the newly deleted messages.
+
+                                    **Changes**: Before Zulip 11.0 (feature level ZF-215011), this list was
+                                    not guaranteed to be sorted.
 
                                     [client-capabilities]: /api/register-queue#parameter-client_capabilities
                                   items:

zerver/tests/test_events.py

@@ -3938,7 +3938,10 @@ class NormalActionsTest(BaseAction):
         hamlet = self.example_user("hamlet")
         msg_id = self.send_stream_message(hamlet, "Verona")
         msg_id_2 = self.send_stream_message(hamlet, "Verona")
-        messages = [Message.objects.get(id=msg_id), Message.objects.get(id=msg_id_2)]
+        # Pass messages in reverse sorted order, so we can test that
+        # the backend is sorting the messages_ids sent in the delete
+        # event.
+        messages = [Message.objects.get(id=msg_id_2), Message.objects.get(id=msg_id)]
         with self.verify_action(state_change_expected=True) as events:
             do_delete_messages(self.user_profile.realm, messages, acting_user=None)
         check_delete_message(
@@ -3948,6 +3951,7 @@ class NormalActionsTest(BaseAction):
             num_message_ids=2,
             is_legacy=False,
         )
+        self.assertEqual(events[0]["message_ids"], sorted(events[0]["message_ids"]))
 
     def test_do_delete_message_stream_legacy(self) -> None:
         """