Introduce AccessibilityPointerMotionFilter

This introduces a new input event filter only for filtering motion
events from cursor devices.
This allows the filter to consume some amount of the relative motion
events before the curosor location in the screen is determined by
PointerChoreographer.
Accessibility fullscreen magnification will use this filter.

Bug: 379646448
Bug: 361817142
Test: Manually tested with feature changes that comes later
Flag: com.android.server.accessibility.enable_magnification_follows_mouse_with_pointer_motion_filter
Change-Id: Ic9cea2b9a894fd2259d7ae8c60abe5ea50cf87d9