message send: Don't create user data list with inline `for`.

This will make the code more readable, and will allow creating local
variables within the loop for reuse.

zerver/lib/actions.py

@@ -1972,7 +1972,9 @@ def do_send_messages(
         else:
             user_list = list(user_ids)
 
-        users = [
+        users: List[Dict[str, Union[int, List[str], bool]]] = []
+        for user_id in user_list:
+            users.append(
                 dict(
                     id=user_id,
                     flags=user_flags.get(user_id, []),
@@ -1982,8 +1984,7 @@ def do_send_messages(
                     wildcard_mention_notify=(user_id in send_request.wildcard_mention_user_ids),
                     sender_is_muted=(user_id in send_request.muted_sender_user_ids),
                 )
-            for user_id in user_list
-        ]
+            )
 
         if send_request.message.is_stream_message():
             # Note: This is where authorization for single-stream