Merge branch 'update-soft-email-confirmation-feature-flag-yaml' into 'master'

Update soft email confirmation yaml

See merge request gitlab-org/gitlab!43286

config/feature_flags/development/soft_email_confirmation.yml

 ---
 name: soft_email_confirmation
-introduced_by_url: 
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab-foss/-/merge_requests/31245
 rollout_issue_url:
-group: 
+group: group::acquisition
 type: development
 default_enabled: false