Update: Next.js to version 15

[colinmurphy]

Description

We should look at updating Next.js to version 15 as most of the Faust packages are on version 14

Steps to reproduce

npm ls next.js

Additional context

No response

@faustwp/core Version

3.2.3

@faustwp/cli Version

3.2.3

FaustWP Plugin Version

N/A

WordPress Version

N/A

Additional environment details

No response

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