fix(deps): update nextjs monorepo to ^15.5.6

[renovate]

This PR contains the following updates:

Package	Change	Age	Confidence
@next/bundle-analyzer (source)	^15.5.5 -> ^15.5.6
@next/eslint-plugin-next (source)	^15.5.5 -> ^15.5.6
eslint-config-next (source)	^15.5.5 -> ^15.5.6
next (source)	^15.5.5 -> ^15.5.6

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Release Notes

vercel/next.js (@​next/bundle-analyzer)

v15.5.6

Compare Source

[!NOTE]
This release is backporting bug fixes. It does not include all pending features/changes on canary.

Core Changes

• Turbopack: don't define process.cwd() in node_modules #​83452

Credits

Huge thanks to @​mischnic for helping!

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