Make Developer flow work with Issue Assignment Trigger

Problem

The Developer (previously Issue-To-MR Flow) was so far always triggered by a button.

With the switch to have Agent identity there is also a service account, which when assigned should trigger the Flow.

There is a high likelihood that some of the data that is currently transferred via the button is not available or only available in a different way when using the service account

Desired Outcome

Developer flow is prepared to also work with Issue assignment.