Variety of small UI tweaks

Updates dialog padding, text opacities on dark theme, progress bar
opacity, ripple background exit speed, remove unnecessary text color
attribute from action menu item layout, fix secondary and tertiary
disabled state text colors.

BUG: 17321765
BUG: 17333263
BUG: 17322159
BUG: 17330086
Change-Id: I14473a985b2c6b853afe7db535a2443e934238e9