Position PiP animation based on actual coordinates

In the previous patchset, we assumed the left/top to be 0/0 which is not
always the case. This could break, for instance, in ActivityEmbedding
setup, where the pip-ing app is on the left side.

Flag: NONE test fix
Bug: 345327260
Test: Verify with apps support auto-enter PiP such as YouTube
Change-Id: Ic2f3289cf0663d0687d5ccd7f4d0250066cb3f67