Migrate GlobalActionsDialogLite to predictive back

As part of the effort to rollout Predictive Back, the old
"just in time" back handlers need to be migrated over to the new
"ahead of time" api (before any animation/feedback can be added).

This is the first change in this API migration, with more to come.

This also adds tests for GlobalActionsDialogLite.

Bug: 238358031
Test: atest GlobalActionsDialogLiteTest
Change-Id: Id8ee4ec97e34e6de63659d30784384e7c9ef9590