Support dynamic game resolution scaling factor

CompatModePackages will read scaling factor from local game manager
service directly and treat any positive value returned as compat scaling
override (with highest priority).

Bug: b/240335717
Test: atest GameManagerServiceTests WmTests:CompatModePackagesTests
Test: adb shell cmd game set --mode 3 --downscale 0.39 $PKG
Change-Id: I95e0ac4af6a2540ba53bfb449b61b1648f3790ad