Ignore nested scrolls from mouse wheel

This CL makes NestedDraggableTest ignore scroll events coming from the
mouse wheel. This is inspired by ag/29733889 and should be removed once
b/388231324 is fixed.

Bug: 378470603
Test: atest NestedDraggableTest
Flag: EXEMPT NestedDraggable is not used yet
Change-Id: Idf1da730c707e167d3683324c06df4fa3cc38379