greetd.dlm: remove

I found this package while cleaning cargoSha256. Its cargoSha256 was
actually wrong and included git dependencies, but it has never been
corrected. I tried fixing it in
NixOS#324316 and requested a maintainer
review, but the maintainer didn't respond to me for the next two weeks.
Upstream was last updated four years ago. Considering we now have much
better login managers for greetd, we should no longer need this package.

pkgs/top-level/all-packages.nix

@@ -30538,7 +30538,7 @@ with pkgs;
   };
 
   greetd = recurseIntoAttrs {
-    dlm = callPackage ../applications/display-managers/greetd/dlm.nix { };
+    dlm = throw "greetd.dlm has been removed as it is broken and abandoned upstream"; #Added 2024-07-15
     greetd = callPackage ../applications/display-managers/greetd { };
     gtkgreet = callPackage ../applications/display-managers/greetd/gtkgreet.nix { };
     regreet = callPackage ../applications/display-managers/greetd/regreet.nix { };