Empty state UI tweaks

- Remove icons from empty state UI
- Increase padding and font sizes
- Remove config change handling as icons no longer need to be toggled
  and padding wasn't changing.
- Remove some other now-unused methods

Bug: 195093229
Test: atest ResolverActivityTest
Test: atest ChooserActivityTest
Test: Visual inspection of UI
Change-Id: Iaa9f7c4e4734e07e76bd9280eb1154c0c67585eb