Fix markdown table showing extra fake column v2

What does this MR do?

• Use display: inline-block to collapse the table width
  • width: fit-content would also work but it doesn't have enough browser compatibility, https://developer.mozilla.org/en-US/docs/Web/CSS/width#Browser_compatibility
• Because it is a inline-block, border-collapse doesn't work and we have to remove the double borders where necessary

There is also an alternative solution, v1 https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/17669, where we revert the changes that introduced the bug and instead scroll the whole container like we used to handle this in notes.

Before	After

Are there points in the code the reviewer needs to double check?

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Tests added for this feature/bug
• Review
  • Has been reviewed by UX
  • Has been reviewed by Frontend
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together
• Internationalization required/considered
• End-to-end tests pass (package-qa manual pipeline job)

What are the relevant issue numbers?

Closes #44024 (closed)