Fix broken links for issues in heatmap

What does this MR do and why?

Describe in detail what your merge request does and why.

Related #1266 (closed)

This was broken by gitlab-org/ruby/gems/gitlab-triage!269 (diffs, comment 1305672320) which was released as 1.29.0 on 2023-03-03: https://gitlab.com/gitlab-org/ruby/gems/gitlab-triage/-/releases#1290-2023-03-03

We updated it on 03-04: !2032 (merged) and that should be when this started breaking.

The change affected the issue title which was fixed by !2037 (merged)

With this MR we fix the issues links in the heatmap

Expected impact & dry-runs

These are strongly recommended to assist reviewers and reduce the time to merge your change.

See https://gitlab.com/gitlab-org/quality/triage-ops/-/tree/master/doc/scheduled#testing-with-a-dry-run on how to perform dry-runs for new policies.

See https://gitlab.com/gitlab-org/quality/triage-ops/-/blob/master/doc/reactive/best_practices.md#use-the-sandbox-to-test-new-processors on how to make sure a new processor can be tested.

Action items

• If adding environment variables for reactive processors, update config/triage-web.yaml and .gitlab/ci/triage-web.yml
• (If applicable) Add documentation to the handbook pages for Triage Operations =>
• (If applicable) Identify the affected groups and how to communicate to them:
  • /cc @person_or_group =>
  • Relevant Slack channels =>
  • Engineering week-in-review