Wiki search has a high number of database calls

Summary

There is a high number of calls to the database when loading group wiki search results.

Steps to reproduce

1. enable the performance bar
2. perform a group wiki search: https://gitlab.com/search?group_id=9970&scope=wiki_blobs&search=test
3. for the search I performed, there were 148 postgres calls

What is the current bug behavior?

There are some (undetected) N+1 calls for wiki search results

Possible fixes

• Wikis do not appear to have a preloads from SearchController in the presenter: app/presenters/search_service_presenter.rb, we can add one
• wiki view is rendered using HAML: app/views/search/results/_wiki_blob.html.haml
• N+1 specs are likely missing data setup (for whatever data is causing the excessive queries):
  • spec/requests/search_controller_spec.rb
  • ee/spec/requests/search_controller_spec.rb