Improve the Zephyr to Xray migration process by allowing Assignee to be a required field

Currently, Xray has this requirement to migrate Zephyr issues into Xray:
"The only mandatory field in Xray's Test, Test Execution, and Test Plan should be the issue Summary and issue Reporter."

However, you should also be allowed to do this migration when you have the Assignee as REQUIRED.
You can make it required through this option in "System" -> "General configuration":

Which doesn't allow the migration to be completed: