Fix broken tests (#3019)

Summary:
Pull Request resolved: #3019

Fix broken tests from D75108474

Differential Revision: D75663439

fbshipit-source-id: e1758f10693d47247dcfda834d266ffd50be9f19

Author: Jasper Shan

torchrec/modules/itep_modules.py

@@ -108,7 +108,7 @@ def __init__(
             self.last_pruned_iter: int = -1
             self.pg: Optional[dist.ProcessGroup] = pg
 
-            if self.lookups is not None:
+            if self.lookups:
                 self.init_itep_state()
             else:
                 logger.info(