Avoid launching activity-based feature to force stop exist actiivty and recreate it.

Root cause: FLAG_ACTIVITY_CLEAR_TASK would cause the exist activity are finished and new one items to be started. It causes Live Transcribe main activity goes onStart call of new activity is followed by onStop call of old activity, which cause the mic stopping.

Solution: Remmove the FLAG_ACTIVITY_CLEAR_TASK.

Bug: 156455425
Test: Manual test
Change-Id: Ia5c490cc4816fe41b704ca8ed9dce2891cf44c9b