Change the misused logic

Refactor from ag/31915496 was wrong. We should skip the transparent
activity tiles when there is a visible task already found not when
visible tasks are not found.

Bug: 397190111
Test: Enter any app, trigger circle to search, see only one tile
produced.
Flag: EXEMPT Bug fix

Change-Id: Ic19710a7d1f5be78e96aa5ac25553358732acf3b