A11y Key interceptor should use IMS for key policy calls

A11y input filter consumes key before IMS processes key
combinations. So, if for certain keys, A11y input filter needs to
let the default shourtcut handling to occur, allow it to directly
call into IMS instead of WM policy which no longer handles all key
shortcuts.

Test: atest KeyInterceptorTest
Bug: 358569822
Flag: com.android.hardware.input.fix_keyboard_interceptor_policy_call
Change-Id: Ib798045616fa7cc989ba3aca4fff32222d53b4a9