Use D instead of d for time units (rapidsai#20910)

This is a continuation of rapidsai#20803

Authors:
  - GALI PREM SAGAR (https://github.com/galipremsagar)
  - Matthew Roeschke (https://github.com/mroeschke)

Approvers:
  - Matthew Roeschke (https://github.com/mroeschke)

URL: rapidsai#20910

Author: galipremsagar

python/cudf/cudf/tests/series/methods/test_explode.py

@@ -1,4 +1,4 @@
-# SPDX-FileCopyrightText: Copyright (c) 2025, NVIDIA CORPORATION.
+# SPDX-FileCopyrightText: Copyright (c) 2025-2026, NVIDIA CORPORATION.
 # SPDX-License-Identifier: Apache-2.0
 
 import numpy as np
@@ -42,7 +42,7 @@ def leaf_value(request):
     elif request.param == "datetime":
         return pd.to_datetime("1900-01-01")
     elif request.param == "timedelta":
-        return pd.to_timedelta("10d")
+        return pd.to_timedelta("10D")
     else:
         raise ValueError("Unhandled data type")