fix RetrievalMethod StrEnum (#26768)

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
Co-authored-by: crazywoola <100913391+crazywoola@users.noreply.github.com>

api/core/datasource/entities/datasource_entities.py

@@ -1,5 +1,5 @@
 import enum
-from enum import Enum
+from enum import StrEnum
 from typing import Any
 
 from pydantic import BaseModel, Field, ValidationInfo, field_validator
@@ -218,7 +218,7 @@ class DatasourceLabel(BaseModel):
     icon: str = Field(..., description="The icon of the tool")
 
 
-class DatasourceInvokeFrom(Enum):
+class DatasourceInvokeFrom(StrEnum):
     """
     Enum class for datasource invoke
     """