Hide searchbar for settings pages where it is not useful

The following discussion from !96873 (merged) should be addressed:

  • @markrian started a discussion: (+2 comments)

    thought: This is another page where it makes little sense (IMO) to have this search feature, since it's a wizard 🤷

    Screenshot_2022-09-09_at_17-49-08_Settings___Gitlab_Org___Gitlab_Ui___GitLab

    Again, outside the scope of this MR.