API: Revert 57042 - MultiIndex.names|codes|levels returns tuples

[rhshadrach]

• closes #xxxx (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.

Manual revert of #57042

Closes #57607

The behavior described in that issue seems quite undesirable, especially for a breaking change.

cc @mroeschke

[mroeschke]

I would be OK reverting this but would like:

1. To expose FrozenList in pandas.api.typing
2. Deprecate the union and difference methods

[rhshadrach]

I would be OK reverting this but would like:

1. To expose FrozenList in pandas.api.typing
2. Deprecate the union and difference methods

Okay with doing this in a follow up? (I likely won't be able to return to this for ~1 week in any case)

[mroeschke]

Okay with doing this in a follow up? (I likely won't be able to return to this for ~1 week in any case)

Yup that's good

[phofl]

Deprecate the union and difference methods

what's the reasoning for those deprecations?

[mroeschke]

what's the reasoning for those deprecations?

Mainly cleanup. IMO if we keep FrozenList and make it available as a public API, that API should be minimal

[mroeschke]

Thanks @rhshadrach