chore(deps): bump next major version to 14.x

[direisc]

Next has an active vulnerability https://security.snyk.io/package/npm/next/13.5.4
Bump the next version to higher version.

I caught some issues running tests locally. If someone can help, I can try to solve the possible issues.

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[direisc]

@dcousens the Experimental ESM Externals flags are set to loose to solve an issue when building admin UI.
This is related to an issue when building a react-day-picker peer dependency with no proper type (ESM/CommonJS).

NextJS shows some ways to solve it at https://nextjs.org/docs/messages/import-esm-externals
The workaround to don't need to fix the type of project or work at react-day-picker is adding experimental: { esmExternals: 'loose' }, to let the Next build try to solve the import.

[direisc]

To clarify the issue around react-day-picker:

[dcousens]

Thanks @direisc, this is really appreciated 💚