Update Carousel bottom padding.

Bug: 1145685
Change-Id: I5bfa2231045c4d5e020133e92b67140116422612
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2519740


Commit-Queue: Tomasz Wiszkowski <ender@google.com>
Reviewed-by: Filip Gorski <fgorski@chromium.org>
Cr-Commit-Position: refs/heads/master@{#824489}