Remove explore routes from sitemap

What does this MR do?

According to https://gitlab.com/gitlab-org/gitlab/-/issues/260334 some routes are not going to be exposed (at least for .com). When we generate the sitemap file some of those urls are included in the file and we don't need to.

In this MR we remove those files from the generated file.

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Separation of EE specific content