Add expand PiP via intent test using FaaS

Add a FaaS flicker test scenario covering expand PiP
to fullscreen via intent case.

Use common assertions for now.

Bug: 412740123
Flag: EXEMPT generic test
Test: atest WMShellFlickerServicePipTests:ExitPipToAppViaIntentTest

Change-Id: I594378a5933fd780f69bba86b14ac3d7cf118b96