Update task-on-home flag to task for every activity launch

Task intent was the original intent that started the task,
which was not being updated for later activity launches.
Therefore, home was not bring to top along with the reused
task while starting the activity again with the task-on-home
flag.

Bug: 122564343
Test: atest ActivityManagerActivityVisibilityTests#testLaunchTaskOnHome

Change-Id: I22a7a9c57c18b8687e41852af27268c37a87fc43