[IMP] Add ability to get batch size from the loader in cuGraph-PyG (r…

…apidsai#3846)

Add a property getter for batch size.  Requested by JoC.

Authors:
  - Alex Barghi (https://github.com/alexbarghi-nv)

Approvers:
  - Rick Ratzel (https://github.com/rlratzel)

URL: rapidsai#3846

python/cugraph-pyg/cugraph_pyg/loader/cugraph_node_loader.py

@@ -351,6 +351,10 @@ def __init__(
         self.__input_nodes = input_nodes
         self.inner_loader_args = kwargs
 
+    @property
+    def batch_size(self) -> int:
+        return self.__batch_size
+
     def __iter__(self):
         self.current_loader = EXPERIMENTAL__BulkSampleLoader(
             self.__feature_store,