silence value_counts dtype inference warning for non pyarrow

Author: lithomas1

pandas/core/algorithms.py

@@ -936,6 +936,7 @@ def value_counts_internal(
             elif (
                 idx.dtype != keys.dtype  # noqa: PLR1714  # # pylint: disable=R1714
                 and idx.dtype != "string[pyarrow_numpy]"
+                and idx.dtype != "str"
             ):
                 warnings.warn(
                     # GH#56161