Test Executions created from the Test Plan should be linked to the Test Plan by default

Test Executions created from the Test Plan should be linked to the Test Plan by default.

this applies to Test Executions created from a selected folder and also from a selected list of Tests.

Currently in the popover dialog, the Test Plan issue key is not present. Besides it, the Test Execution is always linked to the Test Plan even if the user chooses another Test Plan keys (or even if it is deleted).