radicale2: Disable weak crypt htpasswd test

With our recent libxcrypt changes we don't support a lot of weak
algorithms any longer, which made this test fail.

pkgs/servers/radicale/2.x.nix

···
   ];
 
   nativeCheckInputs = with python3.pkgs; [
-    pytest-runner
-    pytest
+    pytestCheckHook
+  ];
+
+  disabledTests = [
+    # uses unsupported crypt method
+    "test_htpasswd_crypt"
   ];
 
   meta = with lib; {