Update FF definitions by Shinya Maeda

This commit updates a couple of FF definitions

config/feature_flags/development/ci_skip_persistent_ref_existence_check.yml

 ---
 name: ci_skip_persistent_ref_existence_check
-introduced_by_url: 
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/32391
 rollout_issue_url: 
-group: 
+group: group::continuous integration
 type: development
 default_enabled: false

config/feature_flags/development/ci_synchronous_artifact_parsing.yml

 ---
 name: ci_synchronous_artifact_parsing
-introduced_by_url: 
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/26247
 rollout_issue_url: 
-group: 
+group: group::progressive delivery
 type: development
 default_enabled: true

config/feature_flags/development/merge_orchestration_service.yml

 ---
 name: merge_orchestration_service
-introduced_by_url: 
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/28532
 rollout_issue_url: 
-group: 
+group: group::continuous integration
 type: development
 default_enabled: true

ee/config/feature_flags/development/disable_merge_trains.yml

 ---
 name: disable_merge_trains
-introduced_by_url: 
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/24844
 rollout_issue_url: 
-group: 
+group: group::continuous integration
 type: development
 default_enabled: false

ee/config/feature_flags/development/feature_flag_api.yml

 ---
 name: feature_flag_api
-introduced_by_url: 
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/18198
 rollout_issue_url: 
-group: 
+group: group::progressive delivery
 type: development
 default_enabled: false