Use screen bounds instead of stable bounds in initial bounds calculation

Default initial bounds in the `DesktopModeLaunchParamsModifier`
should be calculated using `screenBounds` instead of `stableBounds`.

Flag: NONE (bug fix)
Fixes: 352693069
Test: atest WmTests:DesktopModeLaunchParamsModifierTests
Change-Id: Ia2b38b7ac5a810690edeeffc2404df239fc175f7
2 files changed