Removing AdaptiveIconDrawable Checks

As part of the internal cleanup for adaptive icons, we are removing if checks for AdaptiveIconDrawable that are no longer necessary. Also refactoring to follow a more functional programming pattern for easier future refactors.

Bug: 318867282
Flag: EXEMPT BUGFIX
Test: AllAppsSearchImageTest
Change-Id: Id13040bc4fd2ca7e85583d727b228ee390eadc91