Add JIRA remotelinks and prevent duplicated closing messages

What does this MR do?

• Add JIRA remote links to JIRA issues https://developer.atlassian.com/jiradev/jira-platform/guides/other/guide-jira-remote-issue-links/fields-in-remote-issue-links
• Prevent duplication of closing messages when a MR has many closing references
• Small improvements to service code

implements #13232 (closed)
closes #20479 (closed)

Relevant Screenshots

Remote link open status

Remote links closed status