Do not use preview for icon for drive files.

Only use them for the hover preview.

Bug: b/345377359
Change-Id: I326ec3f33444b88adf261cc7178f7fdabad73324
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5606862


Reviewed-by: Michelle Chen <michellegc@google.com>
Commit-Queue: Darren Shen <shend@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1311727}