优化DifyCompareTest和ModelTool中的API调用逻辑，增加重试机制以提高稳定性，更新模型名称获取方式为使用环境变量。

rag2_0/tool/ModelTool.py

@@ -240,7 +240,7 @@ class OpenAiLLM:
 
         self._kwargs = kwargs
 
-    def invoke(self, user_prompt="你是谁？", need_retry=True,**extra_kwargs):
+    def invoke(self, user_prompt="你是谁？", need_retry=True, api_key:str = None, **extra_kwargs):
         # 初始化 OpenAI 客户端
 
         max_retries = 3
@@ -253,10 +253,13 @@ class OpenAiLLM:
             timeout = httpx.Timeout(300.0) 
             self._kwargs["timeout"] = timeout
 
+        if api_key is None:
+            api_key = APIKeyManager.get_api_key()  
+            
         if need_retry:
             while retry_count < max_retries:
                 try:
-                    api_key = APIKeyManager.get_api_key()  
+                    
                     # 使用with语句创建客户端，确保资源会被正确释放
                     with OpenAI(api_key=api_key, base_url=self._url) as client:
                         # 创建 Completion 请求. 超时120s
@@ -276,7 +279,6 @@ class OpenAiLLM:
         else:
             try:
                 # 创建 Completion 请求. 超时120s
-                api_key = APIKeyManager.get_api_key()  
                 # 使用with语句创建客户端，确保资源会被正确释放
                 with OpenAI(api_key=api_key, base_url=self._url) as client:
                     completion = client.chat.completions.create(