Wallet view UI tweaks.

1. Increase the card view bottom margin to avoid weird card shadow.
before: https://hsv.googleplex.com/6352365370212352
after: https://hsv.googleplex.com/5745851513176064
2. Center the card image in card view.
3. Add fade-in animation for the card carousel UI elements when card
carousel is shown; clean up the unnecessary animation for empty state
view -> non-empty state view.
see demo video:
https://drive.google.com/file/d/1Eih4p1uzw_To_SUQsWGYpkd4M85WX2C9/view?usp=sharing&resourcekey=0-oD7hpOg7uKW6xeCmVNvS0Q

Test: manual
Fix: 184905963
Change-Id: Ied2fffef1f2d9bd6bfcfed0985d39cbed3f52cb0