[TASK] Enable a flaky marked postgres test as it seems to work

A functional test has been disabled for postgres because the test
was flaky (what ever this meant exactly) and has been leading to
occassional test run failure.

Using git bisect the first working commit has been way back before
v11.0.0 release tag

  27c7de8a [!!!][TASK] Remove move placeholders #92497

as the commit before has been failing

  64542d62 [TASK] Decouple Dependency logic and domain models in EM

As the patch which has been fixed the related stuff for the flaky
test is not an easy area (or at least I'm not in ) it is really
hard to identify which exactly in that commit has fixed it.

Anyway, as proven through a lot of checkouts sinces this commit and
even current master (run through nightly) passed all green thus
this test is activated again.

Testcommands:
(on different versions/commits + patch | as available )

Build/Scripts/runTests.sh -s functional -d postgres \
typo3/sysext/core/Tests/Functional/DataHandling/IRRE/Foreign...