chore: update default endpoint for ark provider (#7741)

api/core/model_runtime/model_providers/volcengine_maas/client.py

     UserPromptMessage,
 )
 
+DEFAULT_V2_ENDPOINT = "maas-api.ml-platform-cn-beijing.volces.com"
+DEFAULT_V3_ENDPOINT = "https://ark.cn-beijing.volces.com/api/v3"
+
 
 class ArkClientV3:
     endpoint_id: Optional[str] = None
 
     @staticmethod
     def is_legacy(credentials: dict) -> bool:
+        # match default v2 endpoint
         if ArkClientV3.is_compatible_with_legacy(credentials):
             return False
-        sdk_version = credentials.get("sdk_version", "v2")
-        return sdk_version != "v3"
+        # match default v3 endpoint
+        if credentials.get("api_endpoint_host") == DEFAULT_V3_ENDPOINT:
+            return False
+        # only v3 support api_key
+        if credentials.get("auth_method") == "api_key":
+            return False
+        # these cases are considered as sdk v2
+        # - modified default v2 endpoint
+        # - modified default v3 endpoint and auth without api_key
+        return True
 
     @staticmethod
     def is_compatible_with_legacy(credentials: dict) -> bool:
-        sdk_version = credentials.get("sdk_version")
         endpoint = credentials.get("api_endpoint_host")
-        return sdk_version is None and endpoint == "maas-api.ml-platform-cn-beijing.volces.com"
+        return endpoint == DEFAULT_V2_ENDPOINT
 
     @classmethod
     def from_credentials(cls, credentials):
             "sk": credentials['volc_secret_access_key'],
         }
         if cls.is_compatible_with_legacy(credentials):
-            args["base_url"] = "https://ark.cn-beijing.volces.com/api/v3"
+            args["base_url"] = DEFAULT_V3_ENDPOINT
 
         client = ArkClientV3(
             **args

api/core/model_runtime/model_providers/volcengine_maas/volcengine_maas.yaml

         en_US: API Endpoint Host
         zh_Hans: API Endpoint Host
       type: text-input
-      default: maas-api.ml-platform-cn-beijing.volces.com
+      default: https://ark.cn-beijing.volces.com/api/v3
       placeholder:
         en_US: Enter your API Endpoint Host
         zh_Hans: 输入 API Endpoint Host