[Test] Add deepseek v3.2 exp nightly test (#4191)

### What this PR does / why we need it?

- skip the nightly image build when the github event is pull_request
- set imagepullpolicy as alway for multi_node test
- move multi_node tests ahead to have some resource clean first
- do not relevant nightly image build with nightly tests for tolerance

- vLLM version: v0.11.0
- vLLM main:
2918c1b49c

---------

Signed-off-by: hfadzxy <starmoon_zhang@163.com>
Signed-off-by: wangli <wangli858794774@gmail.com>
Co-authored-by: wangli <wangli858794774@gmail.com>

tests/e2e/nightly/multi_node/config/models/DeepSeek-V3_2-Exp-bf16.yaml

@@ -34,8 +34,6 @@ deployment:
   -
     server_cmd: >
         vllm serve Yanguan/DeepSeek-V3.2-Exp-bf16 \
-        --host 0.0.0.0 
-        --port $SERVER_PORT 
         --headless
         --data-parallel-size 2 
         --data-parallel-size-local 1