Open activity directly from notification (outbound transfer)

When user clicks the OPP notification for outbound transfer,
this CL makes the activity start directly from the notification.

Previously the intent was sent to BluetoothOppReceiver first,
which added noticable delay before launching an activity.

Bug: 319050411
Bug: 318610752
Test: m -j;
Test: manual, after sending a file via Bluetooth, click the notification
      titled "Bluetooth Share: Sent files". There should be no lag
      when opening the activity "Outbound Transfers".
Change-Id: I3be36ba6236c95a6c6d97f3bd123254ce27ba15b