[Reauth] Clean up part 2 - remove FIDO toggle from desktop setting

FIDO toggle was replaced by the mandatory reauth toggle.
Now that reauth is fully launched, remove the FIDO toggle and
its related contents.

Bug: 288458283
Change-Id: I7e54115de2800fa8515676b78ac96cee6a920fd3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5508196
Reviewed-by: Kelvin Jiang <kelvinjiang@chromium.org>
Commit-Queue: Siyu An <siyua@chromium.org>
Reviewed-by: Tim <tjudkins@chromium.org>
Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1300953}