Nudge users to install integration if this is nextjs on vercel

[matejminar]

No need for these overwhelming instructions, just install integration and it works.

[matejminar]

when hosting on vercel, env by default is set to vercel-production

[priscilawebdev]

Moved to linear -> https://linear.app/getsentry/issue/TET-427/nudge-users-to-install-integration-if-this-is-nextjs-on-vercel