For remote notices, redirect to the original instead of 404.

For remote notices, redirect to the original instead of 404.

We shouldn't treat these like local statuses, but I don't think a 404
is the right choice either here, because within pleroma-fe, these are
valid URLs. So with remote notices you have the awkward situation
where clicking a link will behave differently depending on whether you
open it in a new tab or not; the new tab will 404 if it hits static-fe.

This new redirecting behavior should improve that situation.