[FedCM] Add arrow icon in button flow modal account rows

Screenshot
https://issues.chromium.org/action/issues/41491333/attachments/55242694?download=false

Bug: 41491333
Change-Id: I02d5aeaeb7fb62be6b4ded1451902a9b4a725bb1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5425454


Commit-Queue: Zachary Tan <tanzachary@chromium.org>
Reviewed-by: Nicolás Peña <npm@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1283368}