Add toast message when RTT request failed.

Bug: 79522243
Test: manual
PiperOrigin-RevId: 198598685
Change-Id: I05144ec734827b29e89bbba5070c9cb0ab06c215
diff --git a/java/com/android/incallui/call/DialerCall.java b/java/com/android/incallui/call/DialerCall.java
index b2c8dcc..56a88b1 100644
--- a/java/com/android/incallui/call/DialerCall.java
+++ b/java/com/android/incallui/call/DialerCall.java
@@ -315,6 +315,7 @@
         @Override
         public void onRttInitiationFailure(Call call, int reason) {
           LogUtil.v("TelecomCallCallback.onRttInitiationFailure", "reason=%d", reason);
+          Toast.makeText(context, R.string.rtt_call_not_available_toast, Toast.LENGTH_LONG).show();
           update();
         }