Fix exception in expandSplitContainerIfNeeded

The exception is because the client side hasn't received
TaskFragmentInfo yet, so we don't have WindowContainerToken
to change the bounds of TaskFragments.
This CL verifies if we have TaskFragmentInfo before
calling expandTaskFragment. If there's no TaskFragmentInfo,
fallback to create new SplitContainer that fills the task
bounds.

Test: atest WMJetpackUnitTests
Test: manual: reproduce steps mentioned in bug
Bug: 232871351

Merged-In: Id8d122f7d95d1c6a3574b02ddd2b6afbc548f853
Change-Id: I83ee6ea32df485bf78db3b50dec8c92d80be8912