Reland "Capability Delegation: match payment-request identifier with spec."

This is a reland of 510b074b,
which was reverted in a730f559

Original change's description:
> Capability Delegation: match payment-request identifier with spec.
>
> The proposed spec [1] specifies a capability through the name defined
> for Permissions Policy [2].  This CL makes the implementation match the
> proposal.
>
> [1] https://wicg.github.io/capability-delegation/spec.html
> [2] https://github.com/w3c/webappsec-permissions-policy/blob/main/features.md
>
> Bug: 1130558
> Change-Id: I926aa030603cfeea10c71fc19f2b232c0d6a5702
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3372328


> Reviewed-by: Stephen McGruer <smcgruer@chromium.org>
> Reviewed-by: David Bokan <bokan@chromium.org>
> Commit-Queue: Mustaq Ahmed <mustaq@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#957608}

Bug: 1130558, 1286707
Change-Id: Ia24b9e690e7cd874d1ce9c1633bb6db08ad971bf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3383679


Reviewed-by: Mustaq Ahmed <mustaq@chromium.org>
Reviewed-by: David Bokan <bokan@chromium.org>
Commit-Queue: Stephen McGruer <smcgruer@chromium.org>
Cr-Commit-Position: refs/heads/main@{#958209}