Use real CameraCompatFreefromPolicy in tests.

CameraCompatFreeformPolicyTests creates a separate CameraCompatFreeformPolicy
 and other camera compat classes. This is due to not being able to inject
 a mock handler in WMService. Instead, spy on the handler and change delayed
 behavior, and use existing classes.

Flag: com.android.window.flags.enable_camera_compat_for_desktop_windowing
Test: atest WmTests:CameraCompatFreeformPolicyTests
Fixes: 384465961
Change-Id: I36ca0205dbeeab80ccb25b3440b8dcbb732c18a0