Remove override density on freeform launch

Currently this is not in the POR and also affects the activity lifecycle
of freeform acitvities. This makes `ActivityLifecycleFreeformTests` to
fail.

Bug: 344599474
Test: atest DesktopTasksControllerTest
Flag: Bug fix
Change-Id: I2dec6a3d3833ee29b421c3518b6d085b4e36b5e0