Remove `sourcegraph` feature flag
What does this MR do and why?
Contributes to #292199 (closed)
Confirmation that the feature flag can be removed: #292199 (comment 2332502071)
References
Please include cross links to any resources that are relevant to this MR. This will give reviewers and future readers helpful context to give an efficient review of the changes introduced.
Edited by Vasilii Iakliushin