Search type doesn't work properly
## Summary
While working on https://gitlab.com/gitlab-org/gitlab/-/issues/474127+ I've discovered that I see exactly the same results with different `search_type`
## Steps to reproduce
1. Open search with `search_type=zoekt` https://gitlab.com/api/v4/projects/278964/search?scope=blobs&per_page=10&search_type=zoekt&search=query_time
1. Open search with `search_type=advanced` https://gitlab.com/api/v4/projects/278964/search?scope=blobs&per_page=10&search_type=advanced&search=query_time
1. You'll see exactly the same set of results
The same can be reproduced in the UI:
1. https://gitlab.com/search?search=query_time&nav_source=navbar&project_id=278964&group_id=9970&search_code=true&repository_ref=master&search_type=advanced
1. https://gitlab.com/search?search=query_time&nav_source=navbar&project_id=278964&group_id=9970&search_code=true&repository_ref=master&search_type=zoekt
UI says it uses a different search engine, but results are the same.
<!-- Describe how one can reproduce the issue - this is very important. Please use an ordered list. -->
## What is the current *bug* behavior?
`search_type` is not respected
<!-- Describe what actually happens. -->
## What is the expected *correct* behavior?
`search_type` should be respected
<!-- Describe what you should see instead. -->
## Relevant logs and/or screenshots
Screenshot with different set of results when you use preferences to disable/enable Zoekt:
{width=1753 height=1191}
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as it's tough to read otherwise. -->
## Possible fixes
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