Revert "nixos/tests/gitlab: add 32 byte secrets"

This reverts commit d6e0d38b84.

We need shorter secrets to continue working, since the earlier
recommendation was too short and there's no way to rotate the them.

nixos/tests/gitlab.nix

@@ -57,9 +57,9 @@ import ./make-test-python.nix ({ pkgs, lib, ...} : with lib; {
           };
         };
         secrets = {
-          secretFile = pkgs.writeText "secret" "r8X9keSKynU7p4aKlh4GO1Bo77g5a7vj";
-          otpFile = pkgs.writeText "otpsecret" "Zu5hGx3YvQx40DvI8WoZJQpX2paSDOlG";
-          dbFile = pkgs.writeText "dbsecret" "lsGltKWTejOf6JxCVa7nLDenzkO9wPLR";
+          secretFile = pkgs.writeText "secret" "Aig5zaic";
+          otpFile = pkgs.writeText "otpsecret" "Riew9mue";
+          dbFile = pkgs.writeText "dbsecret" "we2quaeZ";
           jwsFile = pkgs.runCommand "oidcKeyBase" {} "${pkgs.openssl}/bin/openssl genrsa 2048 > $out";
         };
       };