[PB] Find same change target by surface control

When comparing transitions for identical changes, relying on the
activity's component name is unreliable due to potential multiple
instances. Identifying the same object via its surface control
provides a more reliable approach.

Flag: EXEMPT bugfix
Bug: 376020378
Test: atest BackAnimationControllerTest
Test: launch different instance activity from same Component, verify
the close animation won't get bypassed.

Change-Id: I477a58f6a20455d8f38766337715f7e530be972a