[antlir2][rpms] solv actually can be built on RE

Summary:
Silly me, RE has platform python and dnf libraries available.
It's still gross to be relying on some ambient environment stuff, but this will
speed up image builds by allowing the solv files to be cached.

A future diff will hopefully move these to run in a tiny RE-compatible
appliance image to remove this environment dependency.

Test Plan: waitforsandcastle

Reviewed By: justintrudell

Differential Revision: D51717808

fbshipit-source-id: b7d59f52845ab264a65b69be9de1fe88595fc552

antlir/antlir2/package_managers/dnf/rules/repo.bzl

@@ -56,10 +56,6 @@ def _impl(ctx: AnalysisContext) -> list[Provider]:
             repodata.as_output(),
         ),
         category = "solv",
-        # Invokes a binary using system python3
-        local_only = True,
-        # This has to build locally, but the results are cacheable
-        allow_cache_upload = True,
     )
 
     # Create an artifact that is the _entire_ repository for completely offline