webauthn: implement PublicKeyCredential.parseRequestOptionsFromJSON()
Add implementation and WPT. Flag guarded by
the existing WebAuthenticationJSONSerialization feature flag.
The method effectively creates a WebAuthn get() request from a JSON
dict.
Bug: 40250593
Change-Id: I4083fa2ffa17ec75520e0c38692f165f58e91400
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5634910
Reviewed-by: Adam Langley agl@chromium.org
Commit-Queue: Martin Kreichgauer martinkr@google.com
Cr-Commit-Position: refs/heads/main@{#1316672}