[Media TTT] When a transfer has been initiated, listen to a future so

that we can update the chip to succeeded/failed state once the future
completes.

Bug: 203800665
Test: MediaTttChipControllerTest
Test: `adb shell cmd statusbar media-ttt-chip-add Tablet
TransferInitiated` should show a loading icon for 2 seconds, then
transition to showing an undo button.

Change-Id: Ic01e85c9f66f8cd8624c4fc664787b1a9904742c