Allow wiki pages to be linked to Jira issues when Jira issue is already added to the wiki page.

Replication Steps

1. Integrate Jira with Confluence using the Application Links.
2. Add a reference of Jira ticket to the confluence page. This will automatically create a mentioned in link in Jira.
3. Try to add the wiki page to the same Jira issue. By navigating to More > Link on the issue view.

Actual Result

The page fails to add with an error screen:- "This page is already linked"

Expected Result

Jira should allow wiki pages to be linked to Jira issues eventhough a mentioned in link already exists.