Fix flickering of tasks in desktop window when opened as static tile.

This for loop was added to fix animation glitch if there is scenario of showing splash screen(on config change). Live tiles don't have this issue because we don't create RemoteTargetHandles.

Fix is to set Z-Index as per correct order since current value is same for all tasks.

Test: Manual, Add multiple apps to desktop task, Make it static tile and launch.
Fix: 370731110
Flag: com.android.launcher3.enable_large_desktop_windowing_tile
Change-Id: I9e3f1fd1333b6113423f51309917317febc1805b