[Lint]Style: Convert example to ruff format (#5863)

### What this PR does / why we need it?
This PR fixes linting issues in the `example/` to align with the
project's Ruff configuration.

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

Signed-off-by: root <root@LAPTOP-VQKDDVMG.localdomain>
Co-authored-by: root <root@LAPTOP-VQKDDVMG.localdomain>

pyproject.toml

@@ -48,7 +48,6 @@ plugins.md029.enabled = false # ol-prefix
 line-length = 120
 # Folder to be modified
 exclude = [
-    "examples/**",
     "tests/**",
     "vllm_ascend/**",
 ]