[Dual Shade] Remove the distance calculation from shade transition spec.

For an undetermined reason, the calculation returns 0 sometimes which
causes b/393079108. Since this distance will be soon made redundant by
switching to `verticalContainerReveal()`, it's better to remove this
calculation altogether rather than investigate it.

Bug: 393079108
Test: Unit tests still pass.
Test: Manually verified shade transitions on both narrow and large
 screens.
Flag: com.android.systemui.scene_container
Change-Id: I323d3a16e52ef438248e794835c82cb6abca9e7b