fix: variable aggregator with group and file raise exception (#20581)

api/core/workflow/nodes/variable_aggregator/entities.py

-from typing import Literal, Optional
+from typing import Optional
 
 from pydantic import BaseModel
 
+from core.variables.types import SegmentType
 from core.workflow.nodes.base import BaseNodeData
 
 
         Group.
         """
 
-        output_type: Literal["string", "number", "object", "array[string]", "array[number]", "array[object]"]
+        output_type: SegmentType
         variables: list[list[str]]
         group_name: str