Update Chooser shadows to match Launcher.

This just requires a few parameter changes to align with Launcher
(iconloaderlib), as proposed by digman@ in b/196631965.

Bug: 196631965
Test: asked digman@ to approve a screenshot.
Change-Id: Icca36fe8c5771041bea960478c2be85f0679dc8d
Merged-In: Icca36fe8c5771041bea960478c2be85f0679dc8d