Fix IME flickering when playing Keyguard launching remote animation

When starting the remote animation, before
RemoteAnimationController#goodToGo, WM will traverse all windows to
perform mApplySurfaceChangesTransaction to prepare showing the window
surface if needed.

Howerver, in issue case, IME surface accidientally being in traverse
window list and shown on the screen even Gpay didn't request show IME.

As IME window now is being in ImeContainer, to apply IME surface change
transaction, in WindowState#forAllWindows -> applyInOrderWithImeWindows
-> applyImeWindowsIfNeeded that has logic to apply for IME window when
the traversing window is non-split-screen IME layering target.

However, this logic didn't cover the case if the last IME input target
that interact with IME is not drawn.

For issue case, the last IME input target is the Message app
and invisible because it has obscured by lockscreen.

So during launching the Gpay activity, even Gpay activity is layering
target, since the last IME input target is not visible, in that case
we should not apply IME surface preperation.

As the result, the fix will be:
- Add a check in WindowState#applyImeWindowsIfNeeded to ignore applying
  callback for IME window if the IME input target is not drawn.

Fix: 201987724
Test: atest RemoteAnimationControllerTests#\
         testLaunchRemoteAnimationWithoutImeBehind
Test: manual steps as below:
    0-1) Set secure unlock method (e.g. pattern)
    0-2) Install "Google Pay" app
    0-3) Add a payment method instruction
    1) Start Message app
    2) Click search window and wait IME window appears
    3) Hit power button to lock the device
    4) Tap screen to show Lockscreen
    5) Tap GPay icon
    6) See animation and expect there is no IME flickering behind

Change-Id: I57357ba85501397fa5926ab4dee116c42df24506