CRS Conversion core unit tests are not run

If you download the artifacts of the compile-and-unit-test step from one of the pipeline, you can see in the logs that no unit tests are run :

[INFO] -------------------------------------------------------
[INFO]  T E S T S
[INFO] -------------------------------------------------------
[INFO] 
[INFO] Results:
[INFO] 
[INFO] Tests run: 0, Failures: 0, Errors: 0, Skipped: 0

This is probably following the Java 17 or Spring 6 migration, the JUnit Vintage Engine should be added to the core POM file (or the unit tests migrated to JUnit 5)

When doing so, the tests are properly discovered again, but there are several tests failures and the build is not compiling.