Increase items per message for listener stats (#3522)

As the `PRECONDITION_FAILED` error was wrongly attributed to the entity listener
stats, the items per message were lowered in a vain attempt to fix the error.
But has now been resolved by #3521,
hence increase the limit again.

Author: amCap1712

listenbrainz_spark/stats/incremental/listener/entity.py

@@ -26,7 +26,7 @@ def get_base_path(self) -> str:
 class EntityListenerStatsMessageCreator(UserStatsMessageCreator):
 
     def items_per_message(self):
-        return 500
+        return 5000
 
     @property
     def default_database_prefix(self):