remove get_metadata_cls (#4087)

remove get_metadata_cls. It's only used for V0 engine and has been removed from vLLM already.

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

Signed-off-by: wangxiyuan <wangxiyuan1007@gmail.com>

tests/ut/attention/test_attention_v1.py

@@ -7,8 +7,7 @@ from tests.ut.base import TestBase
 from vllm_ascend.attention.attention_v1 import (AscendAttentionBackend,
                                                 AscendAttentionBackendImpl,
                                                 AscendAttentionMetadataBuilder,
-                                                AscendAttentionState,
-                                                AscendMetadata)
+                                                AscendAttentionState)
 from vllm_ascend.attention.utils import AscendCommonAttentionMetadata
 
 
@@ -21,10 +20,6 @@ class TestAscendAttentionBackend(TestBase):
         self.assertEqual(AscendAttentionBackend.get_impl_cls(),
                          AscendAttentionBackendImpl)
 
-    def test_get_metadata_cls(self):
-        self.assertEqual(AscendAttentionBackend.get_metadata_cls(),
-                         AscendMetadata)
-
     def test_get_builder_cls(self):
         self.assertEqual(AscendAttentionBackend.get_builder_cls(),
                          AscendAttentionMetadataBuilder)