Fixed an issue where the conversation title was showing doubled

For conversations, it's not necessary anymore to extract
the conversation title into the heads up layout.

Fixes: 152655946
Test: add conversation group, observe no double text
Change-Id: I99594ae9e503cf8589603899e0053793be96958a

core/java/android/app/Notification.java

@@ -7158,7 +7158,8 @@ public class Notification implements Parcelable
             CharSequence conversationTitle = !TextUtils.isEmpty(super.mBigContentTitle)
                     ? super.mBigContentTitle
                     : mConversationTitle;
-            if (!TextUtils.isEmpty(conversationTitle) && !hasOnlyWhiteSpaceSenders()) {
+            if (mConversationType == CONVERSATION_TYPE_LEGACY
+                    && !TextUtils.isEmpty(conversationTitle) && !hasOnlyWhiteSpaceSenders()) {
                 return conversationTitle;
             }
             return null;