Tell policy about responsive connections

If a connection is unresponsive, we tell the policy about it. Now, with
this patch, we will also tell the policy that a connection becomes
responsive again. This will allow the policy to cancel the ANR dialog if
it's currently shown, and to stop recurring ANR dialogs if the user was
previously waiting for the app longer.

Bug: 171218828
Test: atest inputflinger_tests
Test: manual test via unresponsive apps
Change-Id: Ifc00601b2c4e44b721a30d5f9ebf786780d1ffd7