BUG: unwrap setitem indexer for ArrowExtensionArray
- [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/v2.0.0.rst` file if fixing a bug or adding a new feature.

Setting values in a pyarrow-backed column with a non-scalar indexer was raising. 

Fixes the following:

```
import pandas as pd

df = pd.DataFrame({"a": [1, 2, 3], "b": [4, 5, 6]}, dtype="int64[pyarrow]")

# IndexError: index 1 is out of bounds for axis 0 with size 1
df.loc[[0, 1], "b"] = 0
```
Thanks @lukemanley 