When creating a Test Execution, the Assignee is not sent in the request and is not set up in the Assignee field of the TE and therefore not inherited by the TesRunAssignee field

Short Description: When creating a Test Execution, the Assignee is not sent in the request and is not set up in the Assignee field of the TE and therefore not inherited by the TesRunAssignee field.

Steps to Reproduce:
1 - Navigate to a Test issue or Test Plan issue.
2 - Create a Test Execution and pick a Assignee.
3 - Navigate to the Test Run page and to the Test Execution issue.

Actual Results: The Test Execution issue does not displayed the assignee user and this is not inherited to the TestRun Assignee field.
Expected Results: Test Execution should be filled with the selected Assignee.