Notify WMShell on aborting auto-enter-pip

Note that this change does not fix the bug listed here. This is to
callback WMShell when the transition is aborted and WMShell can choose
how to handle this.

Bug: 283177443
Test: adb shell dumpsys activity service SystemUIService WMShell
Test: go/winscope and check the SF/WM dump
Change-Id: I8abfc2db47d1f0bfc3d400066936bed354743420