Fix Pydantic UnsupportedFieldAttributeWarning in Settings model (#12600)

Co-authored-by: openhands <openhands@all-hands.dev>

openhands/storage/data_models/settings.py

@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+from typing import Annotated
+
 from pydantic import (
     BaseModel,
     ConfigDict,
@@ -31,7 +33,9 @@ class Settings(BaseModel):
     user_version: int | None = None
     remote_runtime_resource_factor: int | None = None
     # Planned to be removed from settings
-    secrets_store: Secrets = Field(default_factory=Secrets, frozen=True)
+    secrets_store: Annotated[Secrets, Field(frozen=True)] = Field(
+        default_factory=Secrets
+    )
     enable_default_condenser: bool = True
     enable_sound_notifications: bool = False
     enable_proactive_conversation_starters: bool = True