fix(deps): update nextjs monorepo to v14.2.12

[renovate[bot]]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
@next/mdx (source)	14.2.11 -> 14.2.12
eslint-config-next (source)	14.2.11 -> 14.2.12
next (source)	14.2.11 -> 14.2.12

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Release Notes

vercel/next.js (@​next/mdx)

### [`v14.2.12`](https://redirect.github.com/vercel/next.js/compare/v14.2.11...v14.2.12) [Compare Source](https://redirect.github.com/vercel/next.js/compare/v14.2.11...v14.2.12)

vercel/next.js (eslint-config-next)

### [`v14.2.12`](https://redirect.github.com/vercel/next.js/compare/v14.2.11...v14.2.12) [Compare Source](https://redirect.github.com/vercel/next.js/compare/v14.2.11...v14.2.12)

vercel/next.js (next)

### [`v14.2.12`](https://redirect.github.com/vercel/next.js/compare/v14.2.11...v14.2.12) [Compare Source](https://redirect.github.com/vercel/next.js/compare/v14.2.11...v14.2.12)

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