[iOS] Use Dynamic Type in the empty NTP cell

This CL adds Dynamic Type to the cell displayed when the NTP's articles
section is empty.

Bug: 893527
Cq-Include-Trybots: luci.chromium.try:ios-simulator-cronet;luci.chromium.try:ios-simulator-full-configs
Change-Id: If36d6ece1eaac888f606f7730de379aec11ba6be
Reviewed-on: https://chromium-review.googlesource.com/c/1273536
Commit-Queue: Gauthier Ambard <gambard@chromium.org>
Reviewed-by: Justin Cohen <justincohen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#599144}
1 file changed