Enable image blocking for cloud DLP scans on clipboard paste.

The check for blocking based on image scan results now also applies to
cloud DLP scans when the `kDlpScanPastedImages` feature is enabled, in
addition to local scans.

Bug: 432093452
Change-Id: Iede6d0bf7f0e2aa0f57ed2259d3ca9bc1f73b4cf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7147100
Reviewed-by: Dominique Fauteux-Chapleau <domfc@chromium.org>
Reviewed-by: Nancy Xiao <nancylanxiao@google.com>
Commit-Queue: Michał Kaczmarczyk <mickaczmarczyk@google.com>
Cr-Commit-Position: refs/heads/main@{#1544216}