[Actor Login] Decouple ActorLoginMetricsHelper from FedCM content types

This change decouples ActorLoginMetricsHelper from content-layer FedCM
types (specifically content::webid::FederatedLoginResult and
IdentityCredentialSource). Instead, RecordFederatedLoginResult now
accepts the component-level ActorLoginFederatedLoginResult enum
directly.

The conversion from the FedCM result to the metrics enum is now
performed by ActorLoginSiwgController, aligning with its existing
responsibilities.

This is a prerequisite for moving ActorLoginMetricsHelper to
//components.

Bug: 472291829
Change-Id: I5c89ae855e1502ab4fb857f133483bf0ba6f7dcf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7850795
Reviewed-by: Ioana Treib <ioanap@chromium.org>
Commit-Queue: Ginny Huang <ginnyhuang@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1632228}