Implement double tap CUJ in PiP2

Implement transitions flow of double tap CUJ in PiP2
(decoupled from the upcoming animator refactoring).
The "double tap" would be triggered via a broadcast intent
to decouple it from the upcoming PipTouchHandler v2 as well.
(current version of touch handler has certain legacy dependencies,
so it will most probably be reimplemented for PiP2)

Also moved PipDoubleTapHelper into the common package
since we will use it both for pip and pip2.

Bug: 321984612
Test: adb shell am broadcast \
	 -a com.android.wm.shell.pip2.phone.PipScheduler \
	 --ei cuj_code_extra 1
Change-Id: I185d32e5a8d2ad5217afa0eca93a7ca893b84129