top-level/aliases: add filtering

Make aliases in deprecatedPlasma5Packages break eval so we cannot
accidentally shadow packages that have been migrated to Plasma 6.

Author: aidalgol

pkgs/top-level/aliases.nix

@@ -355,15 +355,15 @@ let
       ''
     );
 
-  plasma5Throws = lib.mapAttrs (k: _: makePlasma5Throw k) deprecatedPlasma5Packages;
-
   # Make sure that we are not shadowing something from all-packages.nix.
   checkInPkgs =
     n: alias:
     if builtins.hasAttr n super then abort "Alias ${n} is still in all-packages.nix" else alias;
 
   mapAliases =
     aliases: lib.mapAttrs (n: alias: removeRecurseForDerivations (checkInPkgs n alias)) aliases;
+
+  plasma5Throws = mapAliases (lib.mapAttrs (k: _: makePlasma5Throw k) deprecatedPlasma5Packages);
 in
 
 mapAliases {