Bug fix falsy value of zero (#249)

* certain values are considered False in a boolean context. These include None,0, empty sequences/collections, we are explicity handling that as in our case 0 stands for true

* Update pyiceberg/table/__init__.py

Co-authored-by: Fokko Driesprong <[email protected]>

---------

Co-authored-by: Fokko Driesprong <[email protected]>

Author: MehulBatra

pyiceberg/table/__init__.py

@@ -809,8 +809,8 @@ def new_snapshot_id(self) -> int:
 
     def current_snapshot(self) -> Optional[Snapshot]:
         """Get the current snapshot for this table, or None if there is no current snapshot."""
-        if snapshot_id := self.metadata.current_snapshot_id:
-            return self.snapshot_by_id(snapshot_id)
+        if self.metadata.current_snapshot_id is not None:
+            return self.snapshot_by_id(self.metadata.current_snapshot_id)
         return None
 
     def snapshot_by_id(self, snapshot_id: int) -> Optional[Snapshot]: