[0/n] Create bug fix flag for is desktop mode showing heuristic update

Flag to include the top transparent fullscreen task launched in desktop
mode in the is desktop mode showing heuristic.

Flag: EXEMPT Flag creation:
include_top_transparent_fullscreen_task_in_desktop_heuristic
Bug: 379543275
Test: m

Change-Id: I771ab5f900187f1e709331c525432c453087df79