Remove unused type

[designatednerd]

Addresses #1425 - @knox, a brief look at other things in the networking stack didn't turn up anything we're not still using, but if you see anything else, shout it out. Thanks!

[taher-mosbah]

Hello @designatednerd, in the changelog I see:
BREAKING: Removed the now-unused-in-the-SDK GraphQLHTTPResponseError type. If you were relying on this class, please copy it out of v0.34.1. (#1437)
but doing that I got: 'textEncoding' is inaccessible due to 'internal' protection level and 'statusCodeDescription' is inaccessible due to 'internal' protection level
is it possible to change that please ?

[designatednerd]

You will want to copy the corresponding extension code - you probably want to delete apollo and just make it a simple extension on HTTPURLResponse rather than the more complex ApolloExtension stuff that's in there.

[vincent-paing]

What should I use instead of GraphQLHTTPResponseError?

[knox]

@vincent-paing it's been replaced by ResponseCodeInterceptor.ResponseCodeError