Revert^2 "Verify KeyEvents in IME"

d12c5fe8

Fixed the broken API test in postsubmit by making the newly
introduced InputMethodSession method `default`.

Bug: 331730488
Bug: 378971472
Test: atest CtsInputMethodTestCases InputMethodServiceTest
Flag: android.view.inputmethod.verify_key_event

Change-Id: I6589cc73839acb6b2c3f9256c664b5db7e1ade8a