Autoclick: Reduce panel size on small screens

If a screen is detected to be too small to hold the fully expanded
panel, hide the pause and position button while the panel is expanded.

Demo: http://b/428796322#comment4

Bug: 428796322
Test: AutoclickTypePanelTest
Flag: com.android.server.accessibility.enable_autoclick_indicator
Change-Id: Iff88fb699b89a2e691697aae0b46b6e59c429c79