Add flag FLAG_ACTIVITY_RESET_TASK_IF_NEEDED in LauncherAppsService.

Without this fix:
When starting an activity that was an activity-alias, in the work profile:
If this activity was already running, it caused the activity to be
created a second time instead of restarting the first one.

BUG:21411331

Change-Id: Ieb323885c589caed2675765cd5eed8c311535b92