ci, iwyu: add compat to the list of FILES_WITH_ENFORCED_IWYU

[kevkevinpal]

Description

Motivated by #33725 (comment) this continues the effort to enforce iwyu warnings.

This is only adding the compat dir to the CI script since it seems to already pass the iwyu rules.

Including compat into the CI will keep that part of the codebase hygienic

---

I can close this if it isn't needed or necessary.

[DrahtBot]

The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.

Reviews

See the guideline for information on the review process.
A summary of reviews will appear here.

Conflicts

Reviewers, this pull request conflicts with the following ones:

• #35011 (ci, iwyu: Fix warnings in src/script and treat them as errors by BrandonOdiwuor)

If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.

[maflcko]

Thx, but I don't think it is useful to create conflicting pull requests with already open ones, when the diff is a single line change and that single line conflicts.

It would be better to instead review the existing pull request.

I am going to close this for now. You can pick this up again when the other one is closed or merged, and when this is still relevant after it is closed/merged.