chore: change import path to import directly from module instead of package

PiperOrigin-RevId: 767697759

Author: seanzhougoogle

src/google/adk/tools/bigquery/bigquery_credentials.py

@@ -27,10 +27,10 @@
 from pydantic import BaseModel
 from pydantic import model_validator
 
-from ...auth import AuthConfig
-from ...auth import AuthCredential
-from ...auth import AuthCredentialTypes
-from ...auth import OAuth2Auth
+from ...auth.auth_credential import AuthCredential
+from ...auth.auth_credential import AuthCredentialTypes
+from ...auth.auth_credential import OAuth2Auth
+from ...auth.auth_tool import AuthConfig
 from ..tool_context import ToolContext
 
 BIGQUERY_TOKEN_CACHE_KEY = "bigquery_token_cache"