REF: Series.argsort should dispatch to EA.argsort
### 

- [X] I have checked that this issue has not already been reported.

- [X] I have confirmed this bug exists on the [latest version](https://pandas.pydata.org/docs/whatsnew/index.html) of pandas.

- [X] I have confirmed this bug exists on the master branch of pandas.


### Reproducible Example

```python
N/A
```


### Issue Description

cc @jorisvandenbossche unless I'm missing something?  ive misunderstood the design/behavior of EA.argsort in the past.

### Expected Behavior

NA

### Installed Versions

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Replace this line with the output of pd.show_versions()

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