fix: flaky test_explore_json_async test v2 (#26106)

tests/integration_tests/core_tests.py

@@ -714,10 +714,16 @@ class TestCore(SupersetTestCase):
         keys = list(data.keys())
 
         # If chart is cached, it will return 200, otherwise 202
-        self.assertTrue(rv.status_code in {200, 202})
-        self.assertCountEqual(
-            keys, ["channel_id", "job_id", "user_id", "status", "errors", "result_url"]
-        )
+        assert rv.status_code in {200, 202}
+        if rv.status_code == 202:
+            assert keys == [
+                "channel_id",
+                "job_id",
+                "user_id",
+                "status",
+                "errors",
+                "result_url",
+            ]
 
     @pytest.mark.usefixtures("load_birth_names_dashboard_with_slices")
     @mock.patch.dict(