fix(nextjs): webpack as optional peer-dependency

[belgattitude]

Should close #4632

• fix a warning about a missing peer-dep on webpack.
• should fix install with yarn pnp / pnpm modules linkers

Notes

• Nextjs actually provides webpack (through a ncc'ed dep since Pre-compile more dependencies vercel/next.js#32742).

[AbhiPrasad]

Hey thanks for opening a PR. We're currently discussing this in #4635, feedback welcome!

[AbhiPrasad]

Let's go with this for now, and re-evaluate as needed. Thanks for the help!