remove deprecated model config in mp api settings

Author: esoteric-ephemera

mp_api/client/core/settings.py

@@ -3,7 +3,7 @@
 from typing import List
 
 from pydantic import Field
-from pydantic_settings import BaseSettings
+from pydantic_settings import BaseSettings, SettingsConfigDict
 from pymatgen.core import _load_pmg_settings
 
 from mp_api.client import __file__ as root_dir
@@ -87,5 +87,4 @@ class MAPIClientSettings(BaseSettings):
         _MAX_LIST_LENGTH, description="Maximum length of query parameter list"
     )
 
-    class Config:
-        env_prefix = "MPRESTER_"
+    model_config = SettingsConfigDict(env_prefix="MPRESTER_")