TST: Remove unnecessary pytest fixture scopes
- [x] [Tests added and passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#writing-tests) if fixing a bug or adding a new feature
- [x] All [code checks passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#pre-commit).

I've noticed teardown of fixtures with a greater scope than `function` can take more time e.g. in `pandas/tests/arithmetic/test_numeric.py`

Before:
```
==================================================================================== slowest 30 durations ====================================================================================
0.77s call     pandas/tests/arithmetic/test_numeric.py::TestNumericComparisons::test_numeric_cmp_string_numexpr_path[numexpr-array]
0.76s call     pandas/tests/arithmetic/test_numeric.py::TestNumericComparisons::test_numeric_cmp_string_numexpr_path[python-array]
0.34s call     pandas/tests/arithmetic/test_timedelta64.py::TestTimedelta64ArithmeticUnsorted::test_tda_add_dt64_object_array[python-array-pytz.FixedOffset(-300)]
0.26s call     pandas/tests/arithmetic/test_datetime64.py::TestDatetime64Arithmetic::test_dt64arr_sub_timedeltalike_scalar[python-pytz.FixedOffset(-300)-Timedelta-DataFrame]
0.19s call     pandas/tests/arithmetic/test_datetime64.py::TestDatetime64Arithmetic::test_dt64arr_add_sub_parr[numexpr-Series-DataFrame-None-D]
0.18s teardown pandas/tests/arithmetic/test_datetime64.py::test_dt64arr_addsub_object_dtype_2d[python]
0.14s call     pandas/tests/arithmetic/test_datetime64.py::TestDatetime64SeriesComparison::test_dt64arr_timestamp_equality[numexpr-DataFrame]
0.05s call     pandas/tests/arithmetic/test_datetime64.py::TestDatetime64DateOffsetArithmetic::test_dt64arr_add_sub_relativedelta_offsets[numexpr-DataFrame]
0.05s call     pandas/tests/arithmetic/test_datetime64.py::TestDatetime64DateOffsetArithmetic::test_dt64arr_add_sub_relativedelta_offsets[python-DataFrame]
0.04s teardown pandas/tests/arithmetic/test_timedelta64.py::test_add_timestamp_to_timedelta[python]
0.04s teardown pandas/tests/arithmetic/test_numeric.py::test_empty_str_comparison[python-5-5]
...
================================================================= 29826 passed, 72 xfailed, 12 warnings in 147.93s (0:02:27) =================================================================
```

After
```
==================================================================================== slowest 30 durations ====================================================================================
0.75s call     pandas/tests/arithmetic/test_numeric.py::TestNumericComparisons::test_numeric_cmp_string_numexpr_path[python-array]
0.75s call     pandas/tests/arithmetic/test_numeric.py::TestNumericComparisons::test_numeric_cmp_string_numexpr_path[numexpr-array]
0.28s call     pandas/tests/arithmetic/test_timedelta64.py::TestTimedeltaArraylikeAddSubOps::test_td64arr_add_sub_datetimelike_scalar[numexpr-DataFrame-pytz.FixedOffset(300)-Timestamp]
0.19s call     pandas/tests/arithmetic/test_datetime64.py::TestDatetime64Arithmetic::test_dt64arr_addsub_intlike[numexpr-array-zoneinfo.ZoneInfo(key='UTC')-uint8-Q]
0.15s call     pandas/tests/arithmetic/test_datetime64.py::TestDatetime64ArrayLikeComparisons::test_dt64arr_cmp_scalar_invalid[python-datetime.timezone.utc-Index-foo]
0.12s call     pandas/tests/arithmetic/test_datetime64.py::TestDatetime64SeriesComparison::test_dt64arr_timestamp_equality[numexpr-DataFrame]
0.05s call     pandas/tests/arithmetic/test_datetime64.py::TestDatetime64DateOffsetArithmetic::test_dt64arr_add_sub_relativedelta_offsets[numexpr-DataFrame]
0.05s call     pandas/tests/arithmetic/test_datetime64.py::TestDatetime64DateOffsetArithmetic::test_dt64arr_add_sub_relativedelta_offsets[python-DataFrame]
0.03s call     pandas/tests/arithmetic/test_timedelta64.py::TestTimedeltaArraylikeAddSubOps::test_timedelta64_ops_nat[numexpr]
0.03s call     pandas/tests/arithmetic/test_timedelta64.py::TestTimedeltaArraylikeAddSubOps::test_timedelta64_ops_nat[python]
0.03s call     pandas/tests/arithmetic/test_datetime64.py::TestDatetime64ArrayLikeComparisons::test_dt64arr_cmp_arraylike_inva
...
================================================================= 29826 passed, 72 xfailed, 12 warnings in 141.15s (0:02:21) =================================================================
```
thx @mroeschke 