Avoid warning from cudf regardning an upcoming change of behavior whe…

…n applying a groupby to a list with only a single element refer: https://github.com/rapidsai/cudf/blob/branch-24.02/python/cudf/cudf/core/groupby/groupby.py#L281

morpheus/modules/payload_batcher.py

@@ -147,7 +147,12 @@ def _batch_dataframe_by_group(df: cudf.DataFrame) -> typing.List[cudf.DataFrame]
             # Period object conversion is not supported in cudf
             df[period_column] = df[period_column].to_pandas().dt.to_period(period).astype('str')
 
-        groups = df.groupby(group_by_columns)
+        if len(group_by_columns) == 1:
+            group_by_columns_ = group_by_columns[0]
+        else:
+            group_by_columns_ = group_by_columns
+
+        groups = df.groupby(group_by_columns_)
 
         dfs = []
         for _, group in groups: