updated model to fetch from spaces keys

app.py

@@ -40,7 +40,7 @@ model = HfApiModel(
 token = os.environ["HF_TOKEN"],
 max_tokens=2096,
 temperature=0.5,
-model_id='mistralai/Mistral-7B-instruct-v0.3',# it is possible that this model may be overloaded
+model_id= os.environ['MODEL'],# it is possible that this model may be overloaded
 custom_role_conversions=None,
 )