fix(mdx): switch to official next-mdx-remote v5

[sabertazimi]

Pull Request

This PR Contains

• [ ] bugfix
• [ ] new feature
• [ ] code refactor
• [ ] test update
• [ ] typo fix
• [ ] metadata update

Motivation / Use-Case

Test-Case

I have verified these changes via:

• [ ] Code inspection only, or
• [ ] Newly added/modified unit tests, or
• [ ] No unit tests but ran on a real repository, or
• [ ] Both unit tests + ran on a real repository

Breaking Changes

Additional Info