Fix DatetimeAccessor.strftime errors due to upstream changes

[spencerkclark]

This PR addresses the following upstream build errors (#10548) by explicitly converting the intermediate strftime results to NumPy arrays before reshaping.

FAILED test_accessor_dt.py::TestDatetimeAccessor::test_strftime - NotImplementedError: <class 'pandas.core.arrays.string_arrow.ArrowStringArrayNumpySemantics'> does not support reshape as backed by a 1D pyarrow.ChunkedArray.
FAILED test_accessor_dt.py::TestDatetimeAccessor::test_dask_accessor_method[strftime-%Y-%m-%d %H:%M:%S] - NotImplementedError: <class 'pandas.core.arrays.string_arrow.ArrowStringArrayNumpySemantics'> does not support reshape as backed by a 1D pyarrow.ChunkedArray.
FAILED test_accessor_dt.py::test_cftime_strftime_access[360_day] - NotImplementedError: <class 'pandas.core.arrays.string_arrow.ArrowStringArrayNumpySemantics'> does not support reshape as backed by a 1D pyarrow.ChunkedArray.
FAILED test_accessor_dt.py::test_cftime_strftime_access[365_day] - NotImplementedError: <class 'pandas.core.arrays.string_arrow.ArrowStringArrayNumpySemantics'> does not support reshape as backed by a 1D pyarrow.ChunkedArray.
FAILED test_accessor_dt.py::test_cftime_strftime_access[366_day] - NotImplementedError: <class 'pandas.core.arrays.string_arrow.ArrowStringArrayNumpySemantics'> does not support reshape as backed by a 1D pyarrow.ChunkedArray.
FAILED test_accessor_dt.py::test_cftime_strftime_access[all_leap] - NotImplementedError: <class 'pandas.core.arrays.string_arrow.ArrowStringArrayNumpySemantics'> does not support reshape as backed by a 1D pyarrow.ChunkedArray.
FAILED test_accessor_dt.py::test_cftime_strftime_access[gregorian] - NotImplementedError: <class 'pandas.core.arrays.string_arrow.ArrowStringArrayNumpySemantics'> does not support reshape as backed by a 1D pyarrow.ChunkedArray.
FAILED test_accessor_dt.py::test_cftime_strftime_access[julian] - NotImplementedError: <class 'pandas.core.arrays.string_arrow.ArrowStringArrayNumpySemantics'> does not support reshape as backed by a 1D pyarrow.ChunkedArray.
FAILED test_accessor_dt.py::test_cftime_strftime_access[noleap] - NotImplementedError: <class 'pandas.core.arrays.string_arrow.ArrowStringArrayNumpySemantics'> does not support reshape as backed by a 1D pyarrow.ChunkedArray.
FAILED test_accessor_dt.py::test_cftime_strftime_access[proleptic_gregorian] - NotImplementedError: <class 'pandas.core.arrays.string_arrow.ArrowStringArrayNumpySemantics'> does not support reshape as backed by a 1D pyarrow.ChunkedArray.
FAILED test_accessor_dt.py::test_cftime_strftime_access[standard] - NotImplementedError: <class 'pandas.core.arrays.string_arrow.ArrowStringArrayNumpySemantics'> does not support reshape as backed by a 1D pyarrow.ChunkedArray.