Add key_for_fallback_message_id in ServiceDeskEmail
What does this MR do and why?
Adds a method key_for_fallback_message_id which is in IncomingEmail but not ServiceDeskEmail.
Currently, anyone using the custom mailbox will not receive emails with a Reference header unless they're directly addressed to their Service Desk address using the To header.
How to set up and validate locally
See @qmnguyen0711's excellent note
MR acceptance checklist
This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.
-
I have evaluated the MR acceptance checklist for this MR.
Related to #364118 (closed)
Edited by charlie ablett