fix(django): duplicate --failfast check (#84)

neotest_python/django_unittest.py

@@ -70,6 +70,7 @@ class DjangoNeotestAdapter(CaseUtilsMixin, NeotestAdapter):
             def add_arguments(cls, parser):
                 DiscoverRunner.add_arguments(parser)
                 parser.add_argument("--verbosity", nargs="?", default=2)
+                if "failfast" not in parser.parse_args([]):
                     parser.add_argument(
                         "--failfast",
                         action="store_true",