Use search_service to determine type

What does this MR do and why?

Related to #434899 (closed)

Customer reported issues in Slack thread (internal) with seeing Advanced search syntax for group level API searches (when they should be seeing Zoekt). I noticed in Kibana (internal) that the search_type is being reported incorrectly as advanced_search for API searches but there are zoekt_calls present.

This MR fixes the reporting and adds a spec to test it out

Screenshots or screen recordings

N/A

How to set up and validate locally

To test functionality for Zoekt search and index:

1. enable zoekt in gdk
2. configure zoekt in your environment
3. enable it for a namespace
4. perform an API group level search for that namespace
5. verify in log/api_json.log that the meta.search.type is reported correctly as zoekt. On master it will report as advanced_search

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.