Discover - Have access to the Issue.links to group issues together with the same Jira epic/link

### Problem Statement

I believe the underlying problem is grouping of the Error events.

But the use case itself would be to get a discover list of error titles and linked url from Jira for instance and then have the count so they are grouped.

Currently it's not possible to access the links. Only the Issue without any depth.

### Solution Brainstorm

_No response_

### Product Area

Discover

┆Issue is synchronized with this [Jira Improvement](https://getsentry.atlassian.net/browse/FEEDBACK-2318) by [Unito](https://www.unito.io)

Start in the Discover product area and trace how the Issue object is exposed, focusing on the currently shallow Issue.links access described in the report. Confirm how linked Jira URLs and shared epics should appear in grouped error-event results; done means the requested links are accessible and grouping can use them with counts.

Written by the indexing model from the issue text.