[flexiglass] Parameterize NotificationStackScrollLayoutTest

Some tests were not relevant with the flag off, because they are testing
swipes and flings. Some should keep passing in both configurations.

Bug: 376236758
Test: atest NotificationStackScrollLayoutTest
Flag: com.android.systemui.scene_container
Change-Id: Idd935b8cf17508d5ecf5374054b89006ee5b84d0