Use insets updates to get IME changes [1/N]

Use DisplayInsetsController's OnInsetsChangedListener
to get callbacks into PiP upon IME visibility and height
changes.

This is accomplished through querying the stable bounds
of the display cached by PipDisplayLayoutState and through
querying the InsetsSource with the id of ID_IME.

This is done as a part of PiP2's implementation of task
being moved upon IME appearing/disappearing.

Bug: 352596856
Flag: com.android.wm.shell.enable_pip2_implementation
Test: atest ImeListenerTest
Change-Id: I49ff24a3f7b0bdfee11fed01ab4d747ef3435b1f