Fixed an issue where the largeIcon wouldn't be shown for non-shortcuts

We should only use the shortcut icon if it's available

Bug: 150905003
Test: add group message from Notify with largeIcon
Change-Id: Icd5b0991b34fbfb517344cc6c908a2588973cdca
diff --git a/core/java/android/app/Notification.java b/core/java/android/app/Notification.java
index b58a85e..36898ec 100644
--- a/core/java/android/app/Notification.java
+++ b/core/java/android/app/Notification.java
@@ -7585,7 +7585,9 @@
             }
             boolean isConversationLayout = mConversationType != CONVERSATION_TYPE_LEGACY;
             boolean isImportantConversation = mConversationType == CONVERSATION_TYPE_IMPORTANT;
-            Icon largeIcon = isConversationLayout ? mShortcutIcon : mBuilder.mN.mLargeIcon;
+            Icon largeIcon = isConversationLayout && mShortcutIcon != null
+                    ? mShortcutIcon
+                    : mBuilder.mN.mLargeIcon;
             TemplateBindResult bindResult = new TemplateBindResult();
             StandardTemplateParams p = mBuilder.mParams.reset()
                     .hasProgress(false)