Allow app-process tooling to navigate the AccessibilityNodeInfo tree.

This change bypasses the AccessibilityService and directly
connects AccessibilityInteractionClient to ViewRootImpl's
AccessibilityInteractionController.

Bug: 238391032
Test: Use for Espresso a11y testing
Test: atest AccessibilityEndToEndTest
Change-Id: I0881067a9e5290e208cf3065c149f2a3b433b80c