If the desktop task is visible, increase the count

When the desktop tasks are visible while constructing tasks, increase the number of visible tasks count by 1. Otherwise we might not exclude tasks that are marked as transparent and exludeFromRecents in the constructed list.

Fix: 397190111
Test: Enter desktop, trigger CtS and swipe up. Observe there is only one
desktop tile
Flag: EXEMPT Bug fix

Change-Id: Iabb382b20305a9a5b099bf8ee09a96ac13d0f36d