Merge branch 'shm-add-llama3-to-explain-fix-test-sub-features' into 'master'

llama3 model for /explain, /fix and /test duo slash commands

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/184176



Merged-by: Igor Drozdov <idrozdov@gitlab.com>
Approved-by: Igor Drozdov <idrozdov@gitlab.com>
Co-authored-by: Patrick Cyiza <jpcyiza@gitlab.com>