Handle markdown-link-check flaky failures

[adam-christian-software]

Is your feature request related to a problem? Please describe.

There have been some flaky failures of the markdown-link-check action where an external page cannot be reached. There have been a few times where the link check will fail, but upon re-run, they pass.

Related to: #3058 (comment)

Describe the solution you'd like

I would recommend either two approaches:

1. Perform a retry
2. Have some sort of exclude clause for external pages

Describe alternatives you've considered

No response

Additional context

No response

[snazy]

I think as a mitigation we can remove the workflow from the required checks to unblock PRs.

The check produces false failures, links that are correctly working are reported as not working. This is potentially happening due to rate-limiters along the way from GH workflow runners to the actual sites.

Created #3102 for this.