Return an empty list in `KojiResolver.get_compatible_base_module_modulemds`.
For KojiResolver, this method returns always an empty list. The compatible modules are
defined by the Koji tag inheritance, so there is no need to find out the compatible
base modules on MBS side.
This makes `mse.get_base_module_mmds` to ignore virtual streams and just use
the input base module as the only module without finding the compatible
base modules.