[FedCM] Only Enable the ContinueOnBundle OT on desktop

Bug: 40262526
Change-Id: Ib1762a491cbe1ae0fb0b19dc336182db39ef3b9a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5462622


Reviewed-by: Christian Biesinger <cbiesinger@chromium.org>
Auto-Submit: Yi Gu <yigu@chromium.org>
Commit-Queue: Yi Gu <yigu@chromium.org>
Commit-Queue: Christian Biesinger <cbiesinger@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1288863}