picard: set localedir without relying on bash eval

To be able to remove the bash-eval behavior for setupPyGlobalFlags, we
change $out to use placeholder "out" instead.

Confirmed that the locales are still loaded from the correct path as
demonstrated in #284050.

pkgs/by-name/pi/picard/package.nix

@@ -62,7 +62,7 @@ pythonPackages.buildPythonApplication rec {
     pyyaml
   ];
 
-  setupPyGlobalFlags = [ "build" "--disable-autoupdate" "--localedir=$out/share/locale" ];
+  setupPyGlobalFlags = [ "build" "--disable-autoupdate" "--localedir=${placeholder "out"}/share/locale" ];
 
   preCheck = ''
     export HOME=$(mktemp -d)