[3.19] main/python3: upgrade to 3.11.9
Also adds explicit dependency on libexpat>=2.6.0 since pyexpat now uses the new "reparse deferral" APIs in Expat 2.6.x:
We are currently working on getting Alpine Linux 3.21 out. This means that merge requests that are not aimed to help with that (only affecting testing, new aports) have a lower priority at the moment. Please be patient, they will be eventually picked up.
Also adds explicit dependency on libexpat>=2.6.0 since pyexpat now uses the new "reparse deferral" APIs in Expat 2.6.x: