a11y: Add animation effect to the autoclick indicator

Screen recording: http://go/scrcast/NTUwNzMyODE3NzYwMjU2MHwzZjEzZmE0OC02OQ

Change-Id: I085ceda77d3da1b81f96d43f30731b80bf636985
Bug: b/383901288
Test: Verified locally
Flag: com.android.server.accessibility.enable_autoclick_indicator