Merge branch 'mc_rocha-enable-security_policy_bot_avatar-ff-by-default' into 'master'

Remove security_policy_bot_shared_avatar feature flag

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/168315



Merged-by: Rémy Coutable <remy@rymai.me>
Approved-by: Andy Schoenen <asoiron@gitlab.com>
Approved-by: Rémy Coutable <remy@rymai.me>
Reviewed-by: Rémy Coutable <remy@rymai.me>
Co-authored-by: mc_rocha <mrocha@gitlab.com>