This change causes HTTP status codes to be set on cached HTTP responses.
Otherwise, without this change, no status codes at all are set on cached
HTTP responses — which causes all cached responses to default to being
loaded/served with a 200 status code. And as a result of that, if the
cached response is from a 30x redirect, then without this change, when
that cached 30x response is loaded, we don’t follow the redirect —
because we see a 200 status, rather than the expected/original 30x.
Fixes https://github.com/LadybirdBrowser/ladybird/issues/863
Note that this change also reverts the temporary workaround added in
https://github.com/LadybirdBrowser/ladybird/commit/f735c464d3f
(https://github.com/LadybirdBrowser/ladybird/pull/899).