gerrit: fix auth cookies which include subdomains

The recommended way of getting .gitcookies now is to go to
https://googlesource.com/new-password, which sets a subdomain cookie
with domain `.googlesource.com`.

Fix gitcookie parsing to accommodate for this.

BUG=b:358251450
TEST=npm run unit-test-parallel

Change-Id: I6a6a2100f373255ba4261733c53f355059c78527
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/infra/ide/+/5772491
Reviewed-by: Grace Cham <hscham@chromium.org>
Tested-by: Michael Cui <mlcui@google.com>
Commit-Queue: Michael Cui <mlcui@google.com>
(cherry picked from commit 13602f2ea355ea9f017701c41354266a77d78b88)
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/infra/ide/+/5772495
Auto-Submit: Grace Cham <hscham@chromium.org>
Reviewed-by: Keigo Oka <oka@chromium.org>
Commit-Queue: Keigo Oka <oka@chromium.org>
Tested-by: Grace Cham <hscham@chromium.org>

• chromiumide/src/features/gerrit/auth.ts[diff]
• chromiumide/src/test/unit/features/gerrit/auth.test.ts[diff]