Skip record snapshot for changes from PiP task

The transition framework would try to record snapshot before any
transition animation. This in turn causes a bad snapshot being taken
when we leave/exit PiP. Ignore that code path since we do not record
snapshot for PiP task anyway.

Video: http://recall/-/aaaaaabFQoRHlzixHdtY/hkm5SwtKZ2i6kyFMOyeJxf
Bug: 281783504
Test: manually, see video
Change-Id: Iea19a4bb63d03cd18c95c39f68a469d83ac4d018