Fix DLR on multipart messages: we must use pdu with max message seque…

[hartois]

Fix #1190

Description

Fix DLR on multipart messages: we must use pdu with max message sequence number instead of pdu from last response

Checks

• [ ] My pull request adheres to the code style of this project
• [ ] My code requires changes to the documentation
• [ ] I have updated the documentation as required
• [ ] All the tests have passed

Additional Information