[CI] Upgrade vLLM to 20250920 (c60e613) and address config break (#3067)

### What this PR does / why we need it?
Bump main to
c60e6137f0

- Updated imports in `vllm.config` to
`vllm.config.model`(aed16879a9)
https://github.com/vllm-project/vllm/pull/25252

- Refactored `vllm_ascend/sample/sampler.py` to use string values for
`logprobs_mode` instead of the `LogprobsMode` enum, simplifying logprobs
mode handling and improving compatibility with recent vLLM changes
(aed16879a9)
https://github.com/vllm-project/vllm/pull/25252

### Does this PR introduce _any_ user-facing change?
No

### How was this patch tested?
CI passed


- vLLM version: v0.10.2
- vLLM main:
6d8246aaff

---------

Signed-off-by: Yikun Jiang <yikunkero@gmail.com>

.github/workflows/format_pr_body.yaml

@@ -36,7 +36,7 @@ jobs:
 
       - name: Get vLLM version
         run: |
-          VLLM_COMMIT=6d8246aaffff3ebec84767e373212a7b8da328e2
+          VLLM_COMMIT=c60e6137f0bf2034853919b3a9d705d7e06b93cf
           echo "VLLM_COMMIT=https://github.com/vllm-project/vllm/commit/$VLLM_COMMIT" >> $GITHUB_ENV
 
       - name: Checkout repository