[CI] fix kv_cache_type argument (#18594)

Signed-off-by: Andy Xie <andy.xning@gmail.com>

tests/plugins_tests/test_platform_plugins.py

@@ -29,5 +29,5 @@ def test_oot_attention_backend(monkeypatch: pytest.MonkeyPatch):
     # ignore the backend env variable if it is set
     with monkeypatch.context() as m:
         m.setenv(STR_BACKEND_ENV_VAR, STR_INVALID_VAL)
-        backend = get_attn_backend(16, torch.float16, torch.float16, 16, False)
+        backend = get_attn_backend(16, torch.float16, "auto", 16, False)
         assert backend.get_name() == "Dummy_Backend"