Fix submission error handling

app.py

@@ -1,16 +1,16 @@
 import os
 import requests
-from huggingface_hub import hf_hub_download
+import huggingface_hub
 import gradio as gr
 
 webhook_url = os.environ.get("WEBHOOK_URL")
 
 def submit_model(name):
     try:
-        hf_hub_download(repo_id=name, filename="config.json") # sanity check input
-    except FileNotFoundError:
+        huggingface_hub.hf_hub_download(repo_id=name, filename="config.json") # sanity check input
+    except huggingface_hub.utils._errors.FileNotFoundError:
         return "# ERROR: Model does not have a config.json file!"
-    except RepositoryNotFoundError:
+    except huggingface_hub.utils._errors.RepositoryNotFoundError:
         return "# ERROR: Model could not be found on the Hugging Face Hub!"
     except requests.exceptions.HTTPError:
         return "# ERROR: Network error while validating model. Please try again later."