fix: support for redirects with 200 status. Fix crashing dev server w…

[VitaliyR]

…hen have socket error. Follow redirects from proxyRes

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Summary

Fixes WRFL-2263

One of the customers who are using Gatsby uses a 200 redirect

[[redirects]]
from = "/de-DE/*"
to = "/:splat"
status = 200

It works on prod but doesn't in netlify dev

Root cause for that we are not overriding the url if the file is not static, and in case of dev server running on gatsby (or next as well) - it is never static.

See the updated redirects.test.ts -> specifically the site-with-redirect > should do local redirect It creates a simple redirect for /local/* to /:splat with status 200, user navigates for /local/test/exists:

before the change: 404 page not found after the change: keeping url of /local/test/exists but content of /test/exists (as per docs)

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