Improve message when a Test Execution is in a non-executable status

Improve message when a Test Execution is in a non-executable status.

When a Test is a non-executable status, the warning message that appears is:

This Test is in a non-executable status.

Meanwhile, when the Test Execution is in a non-editable status, the message is:

User amgt does not have permission to execute test execution with key CALC-1551.

Resuming, the message should be uniformized. This way, the users will exactly know why they are not able to execute the Test.