Refs #29069 - Install pulpcore-selinux if needed

To work around PUP-2169, the selinux contexts need to be present before
the main Puppet run. Because pulpcore-selinux depends on
python3-pulpcore, the foreman-installer-katello package can't depend on
it.

hooks/pre/31_install_scl_packages.rb

@@ -3,5 +3,6 @@
   packages = []
   packages << 'rh-postgresql12-postgresql-server' if local_postgresql?
   packages << 'rh-redis5-redis' if local_redis?
+  packages << 'pulpcore-selinux' if pulpcore_enabled?
   ensure_packages(packages, 'installed')
 end