[BugFix] Fixes Qwen3-Next enable nz accuracy problem (#4058)

### What this PR does / why we need it?
- Fixes Qwen3-Next enable nz accuracy problem

### Does this PR introduce _any_ user-facing change?
N/A


- vLLM version: v0.11.0
- vLLM main:
83f478bb19

---------

Signed-off-by: Icey <1790571317@qq.com>
Signed-off-by: wxsIcey <1790571317@qq.com>

tests/ut/worker/test_worker_v1.py

@@ -20,7 +20,13 @@ class TestNPUWorker(TestBase):
         self.model_config_mock = MagicMock(spec=ModelConfig)
         self.model_config_mock.dtype = torch.float16
         self.model_config_mock.trust_remote_code = False
-        self.model_config_mock.hf_config = None
+
+        self.hf_config_mock = MagicMock()
+        self.hf_config_mock.model_type = "test_model"
+        if hasattr(self.hf_config_mock, 'index_topk'):
+            delattr(self.hf_config_mock, 'index_topk')
+
+        self.model_config_mock.hf_config = self.hf_config_mock
 
         self.parallel_config_mock = MagicMock(spec=ParallelConfig)
 
@@ -272,9 +278,9 @@ class TestNPUWorker(TestBase):
 
             self.assertIn("Sleep mode is not enabled", str(cm.exception))
 
+    @patch('vllm_ascend.utils._ENABLE_NZ', False)
     @patch("vllm_ascend.worker.worker_v1.sleep_mode_enabled")
     @patch("vllm_ascend.worker.worker_v1.CaMemAllocator")
-    @patch.dict(os.environ, {"VLLM_ASCEND_ENABLE_NZ": "0"})
     def test_wake_up_mode_enabled(self, mock_allocator_class,
                                   mock_sleep_mode_enabled):
         """Test wake_up method when sleep mode is enabled"""