reenable debci tests for mdanalysis

[Drew Parsons <dparsons@debian.org>]

mdanalysis was recently added to the REJECT list for debci testing
since the tests were regularly randomly timing out.

The issue is now dealt with in unstable and trixie with 
2.9.0-12 deactivating all tests, build and autopkgtest.

autopkgtest deactivation is handled by exit 2 in the test script
before running tests, in order to automatically register the 
mdanalysis tests as "flakey".

We are working with upstream to understand the underlying problem
with the tests, and have suggestions that we can try running
on experimental. 
https://github.com/MDAnalysis/mdanalysis/issues/5078
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1108309

I'd therefore like to request mdanalysis now be removed from
the debci REJECT list, so that we can run tests in experimental.
The tests on unstable and trixie (and testing) will simply be marked 
as flakey, 2 minutes to register so not holding up the test servers
for 3 hours.

Thanks,
Drew