TST: fix import in test_hash_pandas_object extension test
Calling `pd.core.util.hashing._default_hash_key` directly after import of pandas fails with an ImportError, but depending on whether you already did some other operations, the import will succeed. That gives intermittent failures in the test suite (I don't know if it happens in pandas itself, but at least we are seeing it in the geopandas test suite: https://github.com/geopandas/geopandas/issues/2911)
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 2.0.x
git pull
```

2. Cherry pick the first parent branch of the this PR on top of the older branch:
```
git cherry-pick -x -m1 d9067ba2922501560e699161ae1c5d8eb62d939c
```

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

```
git commit -am 'Backport PR #53474: TST: fix import in test_hash_pandas_object extension test'
```

4. Push to a named branch:

```
git push YOURFORK 2.0.x:auto-backport-of-pr-53474-on-2.0.x
```

5. Create a PR against branch 2.0.x, I would have named this PR:

> "Backport PR #53474 on branch 2.0.x (TST: fix import in test_hash_pandas_object extension test)"

And apply the correct labels and milestones.

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

Remember to remove the `Still Needs Manual Backport` label once the PR gets merged.

If these instructions are inaccurate, feel free to [suggest an improvement](https://github.com/MeeseeksBox/MeeseeksDev).
                