List accessor

[rohanjain101]

• closes ENH: Add list accessor for PyArrow list types to support __getitem__ #55323(Replace xxxx with the GitHub issue number)
• Tests added and passed if fixing a bug or adding a new feature
• All code checks passed.
• Added type annotations to new arguments/methods/functions.
• Added an entry in the latest doc/source/whatsnew/vX.X.X.rst file if fixing a bug or adding a new feature.

[rohanjain101]

Not sure why doc string test is failing.

[mroeschke]

Minor comment and some mypy issues otherwise LGTM

[rohanjain101]

@mroeschke I'm not really sure how to work around the CI failure, it looks like the issue is that I'm calling _pa_array in arrow accessor which is only defined in the ArrowExtensionArray, but it's also impossible for the Series to not be backed by an ArrowExtensionArray because of the call to _validate in init.

I looked at the old code in StructAccessor and it was also accessing _pa_array directly, not sure how that one passed the check and this one doesn't. Would appreciate some guidance with this.

EDIT: look like it passing now, but I have a number of other CI failures:

   with pytest.raises(pytz.AmbiguousTimeError, match=dtstr):

      DatetimeIndex([dtobj], tz=tz2)

E Failed: DID NOT RAISE <class 'pytz.exceptions.AmbiguousTimeError'>

Looks unrelated.

[mroeschke]

Nice work @rohanjain101!