Fix toggleSoftInput can't hide IME when the app in multi-window mode

CL[1] changed toggleSoftInput behavior with checking the last IME
requested visibility by using
ImeInsetsSourceConsumer#mRequestedVisible to toggle IME.

However, ImeInsetsSourceConsumer#mRequestedVisible will be updated only
when:
1) The IME insets is controllable for the app.
2) The caller uses WindowsInsetsController#{show, hide}

Since by design when the app is in multi-window mode, SystemUI will
take over the insets control for synchronizing task resizing / IME
animation concern, so it ends up making the app unable to receive IME
insets control then affects toggling IME visiblity.

Even though toggleSoftInput has been deprecated since Android S, we
still requires to support its functionality for old apps run in some
platforms by default in multi-window mode (e.g. ARC++ in freeform
windowing mode).

To fix the issue, replace the check logic with
getRootWindowInests().isVisible(ime()) to check the last IME visiblity
from the root window the served view.

[1]: I390dc029e7bcc30c200926a9bfbbbd0268a1f714

Bug: 240886131
Test: atest KeyboardVisibilityControlTest#testToggleSoftInput in ARC++
Change-Id: Iaf7ccc17a7c02711000983db0d65ad095fe9f8fa