fix(nextjs): Don't write to res.end to fix next export

[lforst]

Fixes #6088

When running next export when having a custom _error page and a custom 404 page, Next.js will call the _error's getInitialProps. In this call, a special res object seems to be passed that doesn't have a .end() method.

This PR fixes a bug where we're trying to access that .end property even though it doesn't exist by simply checking for it first. Since exporting will create static pages we don't need to patch .end anyways.

[AbhiPrasad]

In this call, a special res object seems to be passed that doesn't have a .end() method

This seems like a bug with next, isn't response.end part of the node std library response? Or is this a case where the res might be an plain object, and not one with methods.

[lforst]

In this call, a special res object seems to be passed that doesn't have a .end() method

This seems like a bug with next, isn't response.end part of the node std library response? Or is this a case where the res might be an plain object, and not one with methods.

I think in the case of next export we don't really have actual requests & responses because it is just a static export so the passed res and req simply options don't have these methods. I have to admit though, I didn't look at Next.js code for this fix.

[github-actions]

size-limit report 📦

Path	Size
@sentry/browser - ES5 CDN Bundle (gzipped + minified)	19.84 KB (-0.01% 🔽)
@sentry/browser - ES5 CDN Bundle (minified)	61.46 KB (+0.03% 🔺)
@sentry/browser - ES6 CDN Bundle (gzipped + minified)	18.62 KB (0%)
@sentry/browser - ES6 CDN Bundle (minified)	55 KB (+0.02% 🔺)
@sentry/browser - Webpack (gzipped + minified)	20.38 KB (-0.05% 🔽)
@sentry/browser - Webpack (minified)	66.55 KB (-0.14% 🔽)
@sentry/react - Webpack (gzipped + minified)	20.4 KB (-0.03% 🔽)
@sentry/nextjs Client - Webpack (gzipped + minified)	47.67 KB (-0.03% 🔽)
@sentry/browser + @sentry/tracing - ES5 CDN Bundle (gzipped + minified)	26.82 KB (+0.03% 🔺)
@sentry/browser + @sentry/tracing - ES6 CDN Bundle (gzipped + minified)	25.25 KB (-0.01% 🔽)
@sentry/replay ES6 CDN Bundle (gzipped + minified)	43 KB (+0.03% 🔺)
@sentry/replay - Webpack (gzipped + minified)	38.25 KB (+0.04% 🔺)