Code Insights: Remove the setting based api
Created by: vovakulikov
Part of https://github.com/sourcegraph/sourcegraph/issues/31412
Context
This PR simply removes the setting-based API from our codebase and cleans up a little bit the main insight ts type/model by removing visibility
field (which is 100% related only for the setting-based paradigm)
Test plan
- Make sure that there are no regression around core functionality.