Print Preview: Change some file/element names to match convention

Most elements in Print Preview have paths:
print_preview/new/element_name.*

and ids
print-preview-element-name

The sidebar and advanced settings dialog were the two exceptions to this
rule. Change them to match all the other elements.

Bug: none
Change-Id: Iee530c7bf38d4fef3fbeb26d36d0c6c8db225af2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1577973
Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Commit-Queue: Rebekah Potter <rbpotter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#653023}
10 files changed