Turn off cooldown suppression for wm scenario tests

When cooldown is enabled, heads up notifications are not shown for the
first two minutes after phone reboot, which breaks wm tests that
expect notifications to show up for testing.

Fixes: 330177024

Test: atest WMShellFlickerServicePlatinumTests:com.android.wm.shell.flicker.service.splitscreen.platinum.EnterSplitScreenByDragFromNotificationGesturalNavLandscape#enterSplitScreenByDragFromNotification
atest WMShellFlickerServicePlatinumTests:com.android.wm.shell.flicker.service.splitscreen.platinum.EnterSplitScreenByDragFromNotificationGesturalNavPortrait#enterSplitScreenByDragFromNotification

Change-Id: Ibd81dbe176fde66f241483b98ac6a2716c0f91ad