[CI] Optimize nightly CI (#3898)

### What this PR does / why we need it?
This patch mainly fix the the problem of not being able to determine the
exit status of the pod's entrypoint script and some other tiny
optimizations:
1. Shorten wait for server timeout
2. fix typo
3. fix the issue of ais_bench failing to correctly access the proxy URL
in a PD separation scenario.
### Does this PR introduce _any_ user-facing change?

### How was this patch tested?


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

---------

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

tests/e2e/nightly/multi_node/config/models/Qwen3-235B-A3B.yaml

@@ -47,3 +47,4 @@ deployment:
         --no-enable-prefix-caching
         --gpu-memory-utilization 0.9
 benchmarks:
+