[TailoredWarning] Update strings, bump TailoredInfo version

This updates the strings and icons for tailored download warnings to
the new strings authored by UXW for improved download warnings, and
uses the new strings unconditionally. The strings were added in
crrev.com/c/4712666, but this CL removes the dependency on the other
feature flag. Old strings are removed.

Version number of TailoredInfo is bumped to 2 if improved download
warnings are enabled, otherwise it remains at 1. This allows the
server to ascertain whether improved download warnings are enabled.

Internal CL: cl/554543039

Screenshots (before/after - See items 7-9):
https://drive.google.com/drive/folders/1uQ_3IYGWXMy0w-nWHfiVor1zzenCJczu

Bug: 1351925, 1465966
Change-Id: I58f48602fc8cce54ea791135a9861ae29dc885f3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4757579
Reviewed-by: Xinghui Lu <xinghuilu@chromium.org>
Commit-Queue: Lily Chen <chlily@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1180945}