Pandas BUG: .describe() doesn't work for EAs

Pandas version checks

• [x] I have checked that this issue has not already been reported.

• [x] I have confirmed this bug exists on the latest version of pandas.

• [x] I have confirmed this bug exists on the main branch of pandas.

Reproducible Example

import pandas as pd, pint_pandas
s = pd.Series([1, 2, 3], dtype='pint[kg]')
s.describe()

DimensionalityError                       Traceback (most recent call last)
...

Issue Description

https://github.com/hgrecco/pint-pandas/issues/279

Series.describe sets the dtype for the results to Float64Dtype when the input is an EA. pint's Quantity cannot be casted to Float64Dtype. https://github.com/pandas-dev/pandas/blob/35b0d1dcadf9d60722c055ee37442dc76a29e64c/pandas/core/methods/describe.py#L255

Expected Behavior

.describe should return a Series of objectdtype, or the dtype of the EA

Installed Versions

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