Always bring desktop tasks to front

When showDesktop API is called, always bring desktop tasks to front. And
ignore the visibility status of the tasks.
Fixes an issue with launching desktop tasks from launcher when they are
already visible. Skipping the reorder calls causes second invoke from
launcher to hide all tasks.

Bug: 263264985
Test: atest DesktopModeControllerTest DesktopTasksControllerTest
Change-Id: Iaf5b77e24b75bf8dc8f1daeb749fa0e8e71fb232