[Autofill] New APIs for metrics targeting W

Expose new metrics data points to autofill providers starting in W

Bug: 342676602
Test: n/a, API definition only
API-Coverage-Bug: 378916458
Flag: android.service.autofill.autofill_w_metrics
Change-Id: I999af43d8b983a4bbe806b1c8753b89c479faf27