[CI/Build] Fix broken multimodal test

[DarkLight1337]

Turns out this test still fails even after #10106. I didn't see it in the CI log because the command wasn't run after the previous one failed 😅

[github-actions]

👋 Hi! Thank you for contributing to the vLLM project.
Just a reminder: PRs would not trigger full CI run by default. Instead, it would only run fastcheck CI which starts running only a small and essential subset of CI tests to quickly catch errors. You can run other CI tests on top of those by going to your fastcheck build on Buildkite UI (linked in the PR checks section) and unblock them. If you do not have permission to unblock, ping simon-mo or khluu to add you in our Buildkite org.

Once the PR is approved and ready to go, your PR reviewer(s) can run CI to test the changes comprehensively before merging.

To run CI, PR reviewers can do one of these:

• Add ready label to the PR
• Enable auto-merge.

🚀

[youkaichao]

does transformers have plan to fix it?

[DarkLight1337]

I commented on the PR but seems they haven't really fixed it yet.