Rework the JUnit4->JUnit5 migration LLM prompt

[zimmski]

Please help us keep the number of duplicated issues small.

• [x] I have searched the existing issues for my problem.

Brief Description

We note to the model The tests should produce 100 percent code coverage and must compile. which is not correct. We do not want to have more coverage, we just want the same tests migrated.

Reproducer

No response

Logs

Additional Information

No response

Version

v1.0