Update strings for pdf page info

Bug: 339511978
Change-Id: I3ce412e74b7596ea5010e5d734f477a1e92b5cb0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5610822


Reviewed-by: Christian Dullweber <dullweber@chromium.org>
Commit-Queue: Shu Yang <shuyng@google.com>
Cr-Commit-Position: refs/heads/main@{#1312656}