mold: unmark broken on Darwin

`tbb_2022` no longer causes crashes.

pkgs/by-name/mo/mold/package.nix

···
     changelog = "https://github.com/rui314/mold/releases/tag/v${finalAttrs.version}";
     license = lib.licenses.mit;
     platforms = lib.platforms.unix;
-    broken = stdenv.hostPlatform.isDarwin;
     mainProgram = "mold";
     maintainers = with lib.maintainers; [ azahi ];
   };