JiraConnect: Feature Flag integration includes incorrect URL

Clicking on a feature flag link in Jira takes you to the wrong URL?

Jira Link: https://staging.gitlab.com/mnohr/jira-integration/-/feature_flags/286/edit Actual FF Link: https://staging.gitlab.com/mnohr/jira-integration/-/feature_flags/3/edit (edited)

Cause: use of id instead of iid in lib/atlassian/jira_connect/serializers/feature_flag_entity.rb

Proposed fix: use edit_project_feature_flag_url(flag.project, flag) instead