Use autoclick left click icon on accessibility button

Screenshot:
 - light mode: go/screenshot-rzyepo7k64xnnzq
 - dark mode: go/screenshot-8pmdlxhnbe6o6ru

Bug: 397719419
Test: manually verified UI on test devices
Flag: com.android.server.accessibility.enable_autoclick_indicator
Change-Id: Ia56cbcc043bc708abc89c57dcfdf267202bb7cc1