[Python] Python cookbooks are failing against current development

[raulcd]

After updating the release version to 14.0.0 and the development to 15 dev the development cookbooks for arrow seem to be failing due to the following:

File "schema.rst", line 407, in default
Failed example:
    third_schema = pa.schema([
        ("country_code", pa.int32()),
        ("lat", pa.float32()),
        ("long", pa.float32()),
    ])

    try:
        union_schema =  pa.unify_schemas([first_schema, second_schema, third_schema])
    except pa.ArrowInvalid as e:
        print(e)
Exception raised:
    Traceback (most recent call last):
      File "/usr/lib/python3.10/doctest.py", line 1350, in __run
        exec(compile(example.source, filename, "single",
      File "<doctest default[0]>", line 8, in <module>
        union_schema =  pa.unify_schemas([first_schema, second_schema, third_schema])
      File "pyarrow/types.pxi", line 3326, in pyarrow.lib.unify_schemas
      File "pyarrow/error.pxi", line 154, in pyarrow.lib.pyarrow_internal_check_status
      File "pyarrow/error.pxi", line 91, in pyarrow.lib.check_status
    pyarrow.lib.ArrowTypeError: Unable to merge: Field country_code has incompatible types: string vs int32

See: https://github.com/apache/arrow-cookbook/actions/runs/6788921789/job/18454962099

[raulcd]

cc @AlenkaF @jorisvandenbossche

[AlenkaF]

The example is failing due to the change in the error raised by pa.unify_schemas. The change happened in https://github.com/apache/arrow/pull/36846/files and is now raising ArrowTypeError instead of ArrowInvalid. Will make a PR to update the Cookbook example.