Delete feature flag yaml

The feature has been removed in
https://gitlab.com/gitlab-org/gitlab/-/merge_requests/47583

ee/config/feature_flags/development/embed_analytics_report.yml

----
-name: embed_analytics_report
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/35535
-rollout_issue_url: 
-milestone: '13.2'
-type: development
-group: group::analytics
-default_enabled: false