refac: align with the module structure

src/backend/langflow/template/base.py

@@ -1,7 +1,9 @@
-from typing import Any, Union
 from pydantic import BaseModel
 
 
+from typing import Any, Union
+
+
 class Field(BaseModel):
     field_type: str = "str"
     required: bool = False

src/backend/langflow/template/nodes.py

@@ -1,4 +1,5 @@
-from langflow.template.template import Field, FrontendNode, Template
+from langflow.template.base import Field, Template
+from langflow.template.base import FrontendNode
 from langchain.agents.mrkl import prompt
 from langflow.utils.constants import DEFAULT_PYTHON_FUNCTION