DEPR: ArrayManager
- [x] closes #55043 (Replace xxxx with the GitHub issue number)
- [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).
- [x] Added [type annotations](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#type-hints) to new arguments/methods/functions.
- [x] Added an entry in the latest `doc/source/whatsnew/vX.X.X.rst` file if fixing a bug or adding a new feature.

I'm seeing warnings related to the dateutil package upon import of pandas; is this expected?

https://github.com/pandas-dev/pandas/actions/runs/6177889227/job/16769987130?pr=55044#step:5:92

> /opt/hostedtoolcache/Python/3.12.0-rc.2/x64/lib/python3.12/site-packages/dateutil/tz/tz.py:37: DeprecationWarning: datetime.datetime.utcfromtimestamp() is deprecated and scheduled for removal in a future version. Use timezone-aware objects to represent datetimes in UTC: datetime.datetime.fromtimestamp(timestamp, datetime.UTC).
>  EPOCH = datetime.datetime.utcfromtimestamp(0)

cc @jbrockmendel @mroeschke @MarcoGorelli  > I'm seeing warnings related to the dateutil package upon import of pandas; is this expected?

I'm not surprised by the warning itself, but I'd expect it to be showing up on all builds, not specific to this PR > I'd expect it to be showing up on all builds, not specific to this PR

Thanks - maybe it's only incurred by using subprocess like the test added here. And even then, it only seems to happen in certain jobs. handful of comments, generally looks good.  the complexity of this deprecation (as opposed to just warning inside `ArrayManager.__init__`) makes me want to avoid the environment variable pattern in the future Thanks @rhshadrach 