Fix: Let A11y services consume keys if not a multi-key gesture

Only block keys to reach A11y filter if the key is a multi-key
combination gesture like Vol up + Vol down

Test: atest KeygestureControllerTests
Bug: 433733515
Flag: com.android.hardware.input.fix_keyboard_interceptor_policy_call
Change-Id: I3ea12097feac648ef7cb5fcd39dfe77f27250fa4