Revert "Update the usage of receiveFinishedSignal"

Revert "Use Result<InputPublisher::Finished> instead of callback"

Revert submission 13780058-receiveFinishedSignal

Reason for revert:
Caused severe delay in back navigation on IME-focusable window.

Reverted Changes:
I301c6e9c3:Use Result<InputPublisher::Finished> instead of ca...
I43a0f2d31:Update the usage of receiveFinishedSignal

Bug: 167947340
Fix: 182514338
Test: Manually verified as follows:
 1. Set up the device as "Set up offline" mode.
 2. adb shell am start -n com.google.android.dialer/.extensions.GoogleDialtactsActivity
 3. On one terminal, run adb logcat -s InputMethodManager:*
 4. On another terminal, run adb shell input keyevent 4
 5. Make sure that the following message is not shown.
  "Timeout waiting for IME to handle input event after 2500 ms"

Change-Id: Idb3a44b4a920b1482375e26466cd81e3877f3898