Optimize build for Launcher3Quickstep, Launcher3Go and Launcher3QuickstepGo

This CL adds optimizations for Launcher3Quickstep builds by shrinking
unused resources.
- Enabled proguard for Launcher3QuickStep
- Launcher3Quickstep APK size reduced by -61%, 18.9Mb.
- Launcher3QuickstepGo and Launcher3Go APK size reduced by 6.5%, 872kb.

Fix: 346288630
Flag: EXEMPT Updating bp files to optimize the build
Test: Presubmit and Postsubmit builds
Change-Id: I6f8bdee7febbc125e14df3afe7bbd36ba57623f0