Bluetooth: Dismiss pairing dialog on user click

* Existing pairing dialog should be dismissed when user clicks on Yes/No
* In a pairing session with multiple pairing dialogs, this is necessary
  as otherwise the second pairing dialog will not be shown
* Modified unit test to test this behavior
* Launch pairing dialog as UserHandle.CURRENT to avoid Context warnings

Bug: 35833536
Test: make, unit test, pair with Bluetooth devices
Change-Id: I1823b78d287134505f59eab7caca2329ecc3a36f

src/com/android/settings/bluetooth/BluetoothPairingRequest.java

@@ -52,7 +52,7 @@ public final class BluetoothPairingRequest extends BroadcastReceiver {
     if (powerManager.isInteractive() && shouldShowDialog) {
       // Since the screen is on and the BT-related activity is in the foreground,
       // just open the dialog
-      context.startActivity(pairingIntent);
+      context.startActivityAsUser(pairingIntent, UserHandle.CURRENT);
     } else {
       // Put up a notification that leads to the dialog
       intent.setClass(context, BluetoothPairingService.class);