Display related merge request details in expanded workspace list card
# Display related merge request details in expanded workspace list card
MR: Pending
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## Description
As part of our [new designs for Workspaces](https://gitlab.com/groups/gitlab-org/-/epics/18674), we need to display related merge request information in the expanded workspace cards so that users can quickly view and access merge requests associated with their workspace branch using the new `relatedMergeRequests` field from the Workspace GraphQL type created in https://gitlab.com/gitlab-org/gitlab/-/issues/565012+s.
## Visual Changes
{width=861 height=324}
## Acceptance criteria
- [ ] Add "Merge request" section to expanded workspace cards following the design pattern
- [ ] Display merge request link in format "GitLab.org/project-name/!1234" with external link icon
- [ ] External link opens the MR in a new tab with proper security attributes (rel="noopener noreferrer")
- [ ] Handle cases with no related merge requests (hide section)
## TODO: Implementation plan
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issue