Enable torch compile on _allgather_params (#6769)

* Previosuly ZerO3 was crashing when trying to compile _allgather_params
* Disabling grad solves the issue

deepspeed/runtime/zero/partition_parameters.py

@@ -1882,6 +1882,7 @@ def _allgather_params_coalesced(self, param_list, hierarchy=0, quantize=False):
 
         return None
 
+    @torch.no_grad()
     def _allgather_params(self, param_list, hierarchy=0):
         if len(param_list) == 0:
             return