Check eligibility for CheckFileSystemAccessWriteRequest

This CL extends the eligibility checks enforced by
DownloadProtectionDelegate(Android) to
CheckFileSystemAccessWriteRequest. Previously, they were only checked on
the CheckClientDownload code path, causing Android download protection
to incorrectly send pings for non-APK files, non-enabled users, etc.

To achieve that, this CL refactors some of the checks that apply to
CheckClientDownload to reuse them for CheckFileSystemAccessWriteRequest.

Fixed: 416080485
Change-Id: I5471bce33e27a03855658406a982ae079d131ecb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6537688
Reviewed-by: Daniel Rubery <drubery@chromium.org>
Commit-Queue: Lily Chen <chlily@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1460767}