python3Packages.celery: remove pytest-xdist do to flaky test results

The celery test suite fails on high core system, this is likly do to
multiple tests creating or removing the test sqlite database file in
there respectiv cleanup step.

Fixes: #516582

pkgs/development/python-modules/celery/default.nix

@@ -34,7 +34,6 @@
   pytest-celery,
   pytest-click,
   pytest-timeout,
-  pytest-xdist,
   pytestCheckHook,
   python-dateutil,
   python-memcached,
@@ -156,11 +155,6 @@ buildPythonPackage (finalAttrs: {
     pytest-timeout
     pytestCheckHook
   ]
-  ++ lib.optionals stdenv.hostPlatform.isLinux [
-    # Using `pytest-xdist` leads to incomplete tests which hang `pytestRemoveBytecode`
-    # under `sandbox=false` (the default on Darwin).
-    pytest-xdist
-  ]
   ++ lib.concatAttrValues finalAttrs.passthru.optional-dependencies;
 
   disabledTestPaths = [