Group and friend request handlers lose operator identity

Description

When a group application is accepted or rejected, the persisted group request does not reliably retain the handler user ID and may write the handled message under the wrong field name. As a result, clients and administrators cannot identify who processed the request, and the handled message can be missing from the stored request.

Similarly, refusing a friend request stores the refusal result and time but leaves handlerUserID empty, so the operator identity is lost.

Expected behavior

Persist the acting operator in handle_user_id / handlerUserID for both request types, and persist group request fields using the model field names (handled_msg, handle_result, handle_user_id, and handled_time).