Prevent hotseat updates if it is visible to the user.

Test: manual

Fixes: 168653219

Changing app icons under the user's finger could be disruptive. Added a checks for whether the hotseatand all apps predictions are visible and callbacks to update them when they become hidden.

Change-Id: Ib9e6e904e9f662ecfaeea6a2fe21d1d81ba39b96