[Extensions] Use Promise based language in .idl / .webidl schemas

Updates IDL and WebIDL schemas in `extensions/common/api/` to use
Promise based language. This matches the Promise API signatures that are
given priority in the documentation where these methods are shown.

Bug: N/A
Change-Id: Id0c1459990a0d6da275906216b52e1ee881bcf2c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7389978
Reviewed-by: Devlin Cronin <rdevlin.cronin@chromium.org>
Commit-Queue: Oliver Dunk <oliverdunk@chromium.org>
Reviewed-by: Tim <tjudkins@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1565269}
NOKEYCHECK=True
GitOrigin-RevId: f5b1a2e64def338cae837b228554157a16b1c1a8