fix: upgrade @next/mdx from 13.1.6 to 13.5.8

Snyk has created this PR to upgrade @next/mdx from 13.1.6 to 13.5.8.

See this package in npm:
@next/mdx

See this project in Snyk:
https://app.snyk.io/org/krishguptadev/project/4b6a3be2-3c33-41ee-a670-8c88a094faeb?utm_source=github&utm_medium=referral&page=upgrade-pr

Author: snyk-bot