Enable basic ProGuard minification

We can make the ProGuard config more aggressive later.
Want to keep it on the lighter side initially.
This is mainly driven by the desire to fix the bugs mentioned below.

Bug: T78197
Bug: T76279
Change-Id: Ic91e83e6dc4d25780dc8815318aba2e2a0c009fb
Merge "Enable basic ProGuard minification"