SignedExchange: Do not mark CanSignHttpExchangesDraft as critical

This updates test certificates for layout tests removing the critical
flag of CanSignHttpExchangesDraft extension.

Context: https://github.com/WICG/webpackage/issues/238

Bug: 851778
Change-Id: I1cca7d55a4eebd898db45cc212265674a7e9be5a
Reviewed-on: https://chromium-review.googlesource.com/1119725
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Kouhei Ueno <kouhei@chromium.org>
Reviewed-by: Kent Tamura <tkent@chromium.org>
Commit-Queue: Kunihiko Sakamoto <ksakamoto@chromium.org>
Cr-Commit-Position: refs/heads/master@{#573225}
6 files changed