Bluetooth: Add flag for human readable name

* Add hasHumanReadableName() method to CachedBluetoothDevice that
  returns True when BluetoothDevice.getAliasName() is not null nor empty

Bug: 34685932
Test: pair Bluetooth device, send file over Bluetooth, unit tests
Change-Id: I197f3f7f3bcb7d785729473b25638006449ae862
2 files changed