haskell-hledger-iadd: drop obsolete override (the build fails with or without it)

pkgs/development/haskell-modules/configuration-nix.nix

@@ -467,7 +467,4 @@ self: super: builtins.intersectAttrs super {
   # Without this override, the builds lacks pkg-config.
   opencv-extra = addPkgconfigDepend super.opencv-extra (pkgs.opencv3.override { enableContrib = true; });
 
-  # Needs a newer version of brick than lts-8.x provides.
-  hledger-iadd = super.hledger-iadd.override { brick = self.brick_0_19; };
-
 }