Revert "froide: fix initdb not being in PATH"

This reverts commit ae730b371b.

The underlying issue was properly fixed in
https://github.com/NixOS/nixpkgs/pull/426704.
The commit this reverts was a temporary workaround.

pkgs/by-name/fr/froide/package.nix

@@ -135,7 +135,7 @@ python.pkgs.buildPythonApplication rec {
   '';
 
   nativeCheckInputs = with python.pkgs; [
-    (postgresql.withPackages (p: [ p.postgis ])).out
+    (postgresql.withPackages (p: [ p.postgis ]))
     postgresqlTestHook
     pytest-django
     pytest-playwright