Skip checking gem licenses for gitlab-pages

What does this MR do?

Makes it so license finder doesn't use the bundler codepaths for gitlab-pages. Pages only has dev dependencies, so license_finder breaks when it goes to read the dependencies, and fails because they aren't installed.

I tried using an ignored group, but that would only work if we were also using the prepare step in license_finder. (Which would run a bundle install. The other fix would be for us to run our own bundle install --without development test to get a .bundle configfile in the pages codebase. But it seems a bit silly as it wouldn't actually install any gems.

In this MR, we just limit the package managers license finder checks for pages to be golang related only.

Related issues

Fixes current failing builds.

gitlab-com/gl-infra/production#6841 (closed)

Checklist

See Definition of done.

For anything in this list which will not be completed, please provide a reason in the MR discussion

Required

• Merge Request Title, and Description are up to date, accurate, and descriptive
• MR targeting the appropriate branch
• MR has a green pipeline on GitLab.com
• Pipeline is green on dev.gitlab.org if the change is touching anything besides documentation or internal cookbooks
• trigger-package has a green pipeline running against latest commit

Expected (please provide an explanation if not completing)

• Test plan indicating conditions for success has been posted and passes
• Documentation created/updated
• Tests added
• Integration tests added to GitLab QA
• Equivalent MR/issue for the GitLab Chart opened