Fix flakiness for ExternalStylusConnectedDuringTouchGesture

Remove assertions on NotifyDeviceReset args for the integration test,
as these can be flaky and inconsistent for different device types based
on how many displays, touchscreen devices, etc. that the device has.

Bug: 295149130
Test: atest inputflinger_tests:TouchIntegrationTest#ExternalStylusConnectedDuringTouchGesture --rerun-until-failure
Change-Id: Ic8cb4d7053c95a3f955b203017e2a72db9facaee