BUG: fix wrong error message in deprecated 2D indexing of Series with datetime values
Closes #35527

For most Series types, this was properly raising the deprecation warning about 2D being deprecated, but for Series with datetimetz values, this started raising an AssertionError instead of only raising the warning.


LGTM pending green.  I'm OK with this solution, or with working the check into the existing check_ndim. @jorisvandenbossche if you can update @jorisvandenbossche if you can update for the small comments above thanks @jorisvandenbossche  @meeseeksdev backport 1.1.x Owee, I'm MrMeeseeks, Look at me.

There seem to be a conflict, please backport manually. Here are approximate instructions:

1. Checkout backport branch and update it.

```
$ git checkout 1.1.x
$ git pull
```

2. Cherry pick the first parent branch of the this PR on top of the older branch:
```
$ git cherry-pick -m1 03771a2421b8b7c05983a90bf88f26ce71b1649d
```

3. You will likely have some merge/cherry-pick conflict here, fix them and commit:

```
$ git commit -am 'Backport PR #38099: BUG: fix wrong error message in deprecated 2D indexing of Series with datetime values'
```

4. Push to a named branch :

```
git push YOURFORK 1.1.x:auto-backport-of-pr-38099-on-1.1.x
```

5. Create a PR against branch 1.1.x, I would have named this PR:

> "Backport PR #38099 on branch 1.1.x"

And apply the correct labels and milestones.

Congratulation you did some good work ! Hopefully your backport PR will be tested by the continuous integration and merged soon!

If these instruction are inaccurate, feel free to [suggest an improvement](https://github.com/MeeseeksBox/MeeseeksDev).
                 @simonjayhawkins will do the backport Thanks @jorisvandenbossche 