a11y: Plug "ignore minor cursor movement" setting to AutoclickController

Listen to this setting change. Update cursor movement slope accordingly.
When this setting is on, the minimal valid movement that can reset the
scheduler is the cursor area size.

Bug: b/388845718
Test: AutoclickControllerTest
Flag: com.android.server.accessibility.enable_autoclick_indicator
Change-Id: Ide30df27d06b39de852f307b4166a2bc584a4ac7