Remove cookieauth for pubsub handlers, as these are already restricted to admin users by app.yaml.
Remove cookieauth for pubsub handlers, as these are already restricted to admin users by app.yaml.

Bug: 1079092
Change-Id: Ie06e333424f602f52a70a9715a5329940b3ecd2e
Reviewed-on: https://chromium-review.googlesource.com/c/infra/luci/luci-go/+/2208482
Reviewed-by: Nodir Turakulov <ef4933a197ef7b4b3f55f1bec4942aead3637a2a@chromium.org>
Commit-Queue: Brian Ryner <388ea68edb4d8f934960c128120aee09a8f854bf@chromium.org>

luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go