[CI] Reduce the resource consumption of unit tests (#5891)

### What this PR does / why we need it?
Reduce the resource consumption of unit tests: 32U/pr -> 16U /pr

- vLLM version: v0.13.0
- vLLM main:
bde38c11df

---------

Signed-off-by: wangli <wangli858794774@gmail.com>

.github/workflows/_unit_test.yaml

@@ -78,7 +78,9 @@ jobs:
             --ignore tests/ut/model_loader/netloader/test_netloader_elastic.py \
             --ignore tests/ut/kv_connector/test_remote_prefill_lifecycle.py \
             --ignore tests/ut/kv_connector/test_remote_decode_lifecycle.py \
-            --ignore tests/ut/core/test_scheduler_dynamic_batch.py
+            --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
 
       - name: Upload coverage to Codecov
         # only upload coverage when commits merged

.github/workflows/pr_test_light.yaml

@@ -85,7 +85,7 @@ jobs:
     uses: ./.github/workflows/_unit_test.yaml
     with:
       vllm: ${{ matrix.vllm_version }}
-      runner: linux-amd64-cpu-16-hk
+      runner: linux-amd64-cpu-8-hk
       image: quay.nju.edu.cn/ascend/cann:8.2.rc2-910b-ubuntu22.04-py3.11
       type: pr