Prevent proguard related crashloop on weather clock

A crashloop was happening due to "setGoneMargin" not being found.
Adding a proguard rule to keep ConstraintSet methods alleviates this.

Fixes: 322194308
Flag: N/A
Test: Change to weather clock, observe no crashloop
Change-Id: I322a89771b9535b27b68472c714ab33bb8a00814