### 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>