Fix launch existing split pair fail after unfold device

After unfold device then launch split pair, it might got remote
animation cancelled callback. Because when we got this callback,
both split roots still do not have child then we will dismiss
split due to previous error handling.
We should ignore cancelled case for this because cancel should
indicate the transition still not finished, we should not do this
if transition still not finished.

Fix: 231952106
Test: manual
Test: pass existing tests
Change-Id: Iad5bce9025d1dc4a84765898e42289d47759828a