Revert "ceph: remove unused dependency from httpcore"

This reverts commit ea34eac61b because the
dependency was removed from python3Packages.httpcore.

pkgs/by-name/ce/ceph/package.nix

@@ -321,9 +321,6 @@ let
           };
         });
 
-        httpcore = super.httpcore.overridePythonAttrs (old: {
-          nativeCheckInputs = lib.remove self.pproxy old.nativeCheckInputs;
-        });
       };
   };