[Python] pa.scalar(pd.Timedelta) with second or millisecond unit performs invalid conversion

### Describe the bug, including details regarding any error messages, version, and platform.

```python
In [1]: import pandas as pd; import pyarrow as pa

In [9]: pa.scalar(pd.Timedelta(days=1).as_unit("s"))
Out[9]:

In [10]: pa.scalar(pd.Timedelta(days=1).as_unit("ms"))
Out[10]:

In [11]: pa.scalar(pd.Timedelta(days=1).as_unit("us"))
Out[11]:

In [12]: pa.scalar(pd.Timedelta(days=1).as_unit("ns"))
Out[12]:

In [13]: pa.__version__
Out[13]: '12.0.0' # same result with 13.0.0.dev715
```

I would expect all 4 results to return `datetime.timedelta(days=1)`

### Component(s)

Python