Add warning in PTEModel when not defined (#1468)

* Add warning in PTEModel when not defined

* Add missing parans

Author: Jack-Khuu

torchchat/model.py

@@ -1062,5 +1062,6 @@ def forward(self, x, input_pos):
         def setup_caches(self, max_batch_size, max_seq_length):
             pass
 
-except:
+except Exception as e:
+    print(f"Warning: PTEModel (ExecuTorch) not available with exception: {e}")
     pass