Autoclick: Improve scroll click testing

Use a smaller slop distance when hovering panels to improve
clickability.

ABTD run: http://b/430124930#comment4

Bug: 430124930
Test: AutoclickClickTypeTests
Flag: com.android.server.accessibility.enable_autoclick_indicator
Change-Id: I7cbfdb50346125e81c4bdacdfe6e7a4a91481c9f