fix(nextjs): Ignore tunnelRoute when doing static exports

[lforst]

Fixes #8285

Next.js doesn't allow static exports + rewrites. This PR will stop injecting rewrites on static exports.

[github-actions]

size-limit report 📦

Path	Size
@sentry/browser - ES5 CDN Bundle (gzipped + minified)	21.95 KB (+0.66% 🔺)
@sentry/browser - ES5 CDN Bundle (minified)	69.13 KB (+0.83% 🔺)
@sentry/browser - ES6 CDN Bundle (gzipped + minified)	20.29 KB (+0.87% 🔺)
@sentry/browser - ES6 CDN Bundle (minified)	60.38 KB (+0.96% 🔺)
@sentry/browser - Webpack (gzipped + minified)	21.9 KB (+0.79% 🔺)
@sentry/browser - Webpack (minified)	71.51 KB (+0.81% 🔺)
@sentry/react - Webpack (gzipped + minified)	21.92 KB (+0.8% 🔺)
@sentry/nextjs Client - Webpack (gzipped + minified)	50.57 KB (+0.35% 🔺)
@sentry/browser + @sentry/tracing - ES5 CDN Bundle (gzipped + minified)	30.11 KB (+0.51% 🔺)
@sentry/browser + @sentry/tracing - ES6 CDN Bundle (gzipped + minified)	28.14 KB (+0.59% 🔺)
@sentry/replay ES6 CDN Bundle (gzipped + minified)	49.42 KB (0%)
@sentry/replay - Webpack (gzipped + minified)	43.1 KB (0%)
@sentry/browser + @sentry/tracing + @sentry/replay - ES6 CDN Bundle (gzipped + minified)	69.5 KB (+0.23% 🔺)
@sentry/browser + @sentry/replay - ES6 CDN Bundle (gzipped + minified)	61.82 KB (+0.25% 🔺)