p13n: Fix position of wallpaper info dialog

Screen recording: http://shortn/_bZwhgZ0qnK

Bug: b:332327370
Test: Manually verify UI
Change-Id: Idf43e1059aa9c19eac7bce54d57e8e05205b1abe
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5415657


Reviewed-by: Thuong Phan <thuongphan@chromium.org>
Reviewed-by: Jason Thai <jasontt@chromium.org>
Commit-Queue: Wes Okuhara <wesokuhara@google.com>
Cr-Commit-Position: refs/heads/main@{#1281944}