Support dynamic build requires on CentOS 9
Background:
https://fedoraproject.org/wiki/Changes/DynamicBuildRequires
Example of package failing that should not:
https://gitlab.cern.ch/ai-config-team/stomppy/python-stomppy5/-/pipelines/3519837
python3-wheel is correctly not a BuildRequire because it is it is only autogenerated during the %prep phase of the .spec file.
koji and mock should be fine with this and do the correct thing already.
However rpmbuild needs an extra phase.
rpmbuild -br builds a nosrc.rpm package with the BuildRequires in and this has its build dependencies installed in the normal way.
For reference this is what mock does: