Add the pairing string for CSIP supported device

Show the pairing dialog with the hint message
that pairing this device will pair all of the
set member of a coordinated set. If the device
supports CSIP, the message will be shown.

Screenshot: https://screenshot.googleplex.com/8WcrdgBoLRgJjHs

Bug: 178981521
Test: make RunSettingsRoboTests ROBOTEST_FILTER=BlueotohPairingDialog
Change-Id: I5432b7264652dd4485e2669f6004caa4f7459238

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

@@ -344,6 +344,9 @@ public class BluetoothPairingDialogFragment extends InstrumentedDialogFragment i
             pairingViewContent.setVisibility(View.VISIBLE);
             pairingViewContent.setText(mPairingController.getPairingContent());
         }
+        final TextView messagePairingSet = (TextView) view.findViewById(R.id.pairing_group_message);
+        messagePairingSet.setVisibility(mPairingController.isCoordinatedSetMemberDevice()
+                ? View.VISIBLE : View.GONE);
         return view;
     }