Non-flaky slider haptics test

Removing the need of the animator test rule to replicate the desired
conditions. Additionally, the constants asserted are now integer types.

Test: atest SystemUITests:VolumeDialogImplTest
Flag: ACONFIG haptic_volume_slider TRUNKFOOD
Bug: 329282567

Change-Id: Ifa41920a133c74b4cd6d867ff7ab7786f570c3b1