Resend previous inline suggestions when IME hides and shows again

* when IME hides (onInputViewFinish), autofill manager service will
  send an empty inline suggestions response to clear the previous
  non-empty response
* when IME shows again (onInputViewStart), if the focus didn't change,
  the autofill manager service will resend the previous non-empty inline
  suggestions response to the IME

Test: atest android.autofillservice.cts.inline
Test: atest CtsInputMethodTestCases
Bug: 152577411
Bug: 153702698

Change-Id: Ic6a4b1db54c93040dc47c2a0d1cdc2e98f64d8ff