upd _prepare_stream_args after review

Author: annalvova05

airbyte-integrations/connectors/source-tiktok-marketing/source_tiktok_marketing/source.py

@@ -68,12 +68,18 @@ def spec(self, *args, **kwargs) -> ConnectorSpecification:
     @staticmethod
     def _prepare_stream_args(config: Mapping[str, Any]) -> Mapping[str, Any]:
         """Converts an input configure to stream arguments"""
-        credentials = config.get("credentials") or config
-
-        access_token = credentials["access_token"]
-        secret = credentials.get("secret") or credentials.get("environment", {}).get("secret")
-        app_id = int(credentials.get("app_id", 0) or credentials.get("environment", {}).get("app_id", 0))
-        advertiser_id = int(credentials.get("advertiser_id", 0) or credentials.get("environment", {}).get("advertiser_id", 0))
+        credentials = config.get("credentials")
+        if credentials:
+            # used for new config format
+            access_token = credentials["access_token"]
+            secret = credentials.get("secret")
+            app_id = int(credentials.get("app_id", 0))
+            advertiser_id = int(credentials.get("advertiser_id", 0))
+        else:
+            access_token = config["access_token"]
+            secret = config.get("environment", {}).get("secret")
+            app_id = int(config.get("environment", {}).get("app_id", 0))
+            advertiser_id = int(config.get("environment", {}).get("advertiser_id", 0))
 
         return {
             "authenticator": TiktokTokenAuthenticator(access_token),