Add icon pack to ThemePicker.

- Changed fillColor to white for all overlayed icons to ensure they are
all properly tinted in view xml or code
- Introduce NoTintDrawableWrapper to ensure tip dot isn't tinted while
the nav icon drawable is tinted
- Add overlayable_icons_test.xml created from icon pack generation
- Add the ThemePicker package as an overlay target package

Bug: 130788873
Test: visual
Change-Id: Ib6e2ff48800cb75411754b333c0d0ebcfcba5ab1