lauti.tests: fix the eval

After a rename of the attribute the test references were fixed, but not
the test itself. This caused eval failures like:

    $ nix build --no-link -f. lauti.tests
    error:
       … while evaluating the attribute 'lauti'
         at pkgs/by-name/la/lauti/package.nix:45:26:
           44|   passthru.tests = {
           45|     inherit (nixosTests) lauti;
             |                          ^
           46|   };

THe change renames the test as well.

nixos/tests/all-tests.nix

@@ -420,7 +420,7 @@ in
   ecryptfs = runTest ./ecryptfs.nix;
   fscrypt = runTest ./fscrypt.nix;
   fastnetmon-advanced = runTest ./fastnetmon-advanced.nix;
-  eintopf = runTest ./eintopf.nix;
+  lauti = runTest ./lauti.nix;
   ejabberd = runTest ./xmpp/ejabberd.nix;
   elk = handleTestOn [ "x86_64-linux" ] ./elk.nix { };
   emacs-daemon = runTest ./emacs-daemon.nix;