feat:补充边界安全判断

app/src/main/java/com/nnbc123/app/ui/im/fragment/MessageFragment.java

@@ -660,7 +660,7 @@ public class MessageFragment extends TFragment implements ModuleProxy, MessageLi
             }
             if (throwable != null) {
                 throwable.printStackTrace();
-            } else {
+            } else if (privateChatLimitInfo != null) {
                 loadChatLimit(privateChatLimitInfo, sessionIsEmpty);
             }
         }));