docs: disable md link checker for twitter links

[mpoke]

Description

Closes: NA

The md link checker is failing when checking twitter links with status 400 leading to false positives. This is a known issue (see gaurav-nelson/github-action-markdown-link-check#182). Until this is fixed, this PR disables the check for twitter links.

---

Author Checklist

All items are required. Please add a note to the item if the item is not applicable and
please add links to any relevant follow up issues.

I have...

• included the correct docs: prefix in the PR title
• targeted the correct branch (see PR Targeting)
• provided a link to the relevant issue or specification
• reviewed "Files changed" and left comments if necessary
• confirmed all CI checks have passed

Reviewers Checklist

All items are required. Please add a note if the item is not applicable and please add
your handle next to the items reviewed if you only reviewed selected items.

I have...

• Confirmed the correct docs: prefix in the PR title
• Confirmed all author checklist items have been addressed
• Confirmed that this PR only changes documentation
• Reviewed content for consistency
• Reviewed content for thoroughness
• Reviewed content for spelling and grammar
• Tested instructions (if applicable)

[p-offtermatt]

We could instead modify the link checker config to ignore all links to Twitter.
Imo a better solution:

• easier to revert (just 1 place instead of near all twitter links)
• easier to maintain if we add new links to Twitter (we don't have to remember to put the link checker incantation)

see:
ignorePattern from https://github.com/tcort/markdown-link-check#config-file-format used in a configFile supplied to the github action https://github.com/gaurav-nelson/github-action-markdown-link-check#custom-variables