[CI] Skip test_mooncake_layerwise_connector.py in ut (#7147)

### What this PR does / why we need it?
The `test_mooncake_layerwise_connector.py` file in the `ut` test will be
skipped for now and fixed later.

- vLLM version: v0.16.0
- vLLM main:
4034c3d32e

Signed-off-by: MrZ20 <2609716663@qq.com>

.github/workflows/_unit_test.yaml

@@ -73,7 +73,8 @@ jobs:
             --ignore tests/ut/core/test_scheduler_dynamic_batch.py \
             --ignore tests/ut/kv_connector/test_mooncake_connector.py \
             --ignore tests/ut/worker/test_worker_v1.py \
-            --ignore tests/ut/spec_decode/test_mtp_proposer.py
+            --ignore tests/ut/spec_decode/test_mtp_proposer.py \
+            --ignore tests/ut/kv_connector/test_mooncake_layerwise_connector.py
 
       - name: Upload coverage to Codecov
         # only upload coverage when commits merged