Add test for scene animation when distance is not specified yet

If the SwipeAnimation's distance hasn't been calculated, the animation
shouldn't start.
Instead, the scene should remain as it is.

Test: atest DraggableHandlerTest
Bug: 388803469
Flag: com.android.systemui.scene_container
Change-Id: I26f51e4b2155e57c4cbd9b69ec17b4b1ab342d1c