fix: Azure AI Foundry model cannot be used in the workflow (#13323)

Signed-off-by: -LAN- <laipz8200@outlook.com>

api/core/model_runtime/entities/llm_entities.py

@@ -1,5 +1,5 @@
 from decimal import Decimal
-from enum import Enum
+from enum import StrEnum
 from typing import Optional
 
 from pydantic import BaseModel
@@ -8,7 +8,7 @@ from core.model_runtime.entities.message_entities import AssistantPromptMessage,
 from core.model_runtime.entities.model_entities import ModelUsage, PriceInfo
 
 
-class LLMMode(Enum):
+class LLMMode(StrEnum):
     """
     Enum class for large language model mode.
     """

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

@@ -4,6 +4,7 @@ from typing import Any, Optional
 from pydantic import BaseModel, Field, field_validator
 
 from core.model_runtime.entities import ImagePromptMessageContent
+from core.model_runtime.entities.llm_entities import LLMMode
 from core.prompt.entities.advanced_prompt_entities import ChatModelMessage, CompletionModelPromptTemplate, MemoryConfig
 from core.workflow.entities.variable_entities import VariableSelector
 from core.workflow.nodes.base import BaseNodeData
@@ -12,7 +13,7 @@ from core.workflow.nodes.base import BaseNodeData
 class ModelConfig(BaseModel):
     provider: str
     name: str
-    mode: str
+    mode: LLMMode = LLMMode.COMPLETION
     completion_params: dict[str, Any] = {}