Add digital-credentials-get permission policy
This CL adds the digital-credentials-get permissions policy to get the
digital credentials API in <iframe>s.
BUG=346356629
TEST=wpt_internal/digital-credentials/
Low-Coverage-Reason: Testing done in WPT
Change-Id: Idbcf8433fae09383d775b8a3c344d55b9f12dac5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5678955
Reviewed-by: Alex Rudenko alexrudenko@chromium.org
Reviewed-by: Ken Buchanan kenrb@chromium.org
Commit-Queue: Peter Kotwicz pkotwicz@chromium.org
Cr-Commit-Position: refs/heads/main@{#1323731}