[webauthn] Have all FIDO owners own WPT tests.

(Almost) all aspects of webauthn are owned by fido/OWNERS and Kim is OOO.

Bug: 1010934
Change-Id: I1e13d357bcc5f5b4168126d60aa92a4c9a10faa5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1837873
Auto-Submit: Nina Satragno <nsatragno@chromium.org>
Commit-Queue: Martin Kreichgauer <martinkr@google.com>
Reviewed-by: Martin Kreichgauer <martinkr@google.com>
Cr-Commit-Position: refs/heads/master@{#702462}

third_party/blink/web_tests/external/wpt/webauthn/OWNERS

-kpaulhamus@chromium.org
+file://device/fido/OWNERS
 
 # COMPONENT: Blink>WebAuthentication
 # TEAM: identity-dev@chromium.org