bug in print_changed_only in new repr: vector values

```python
import sklearn
import numpy as np
from sklearn.linear_model import LogisticRegressionCV
sklearn.set_config(print_changed_only=True)
print(LogisticRegressionCV(Cs=np.array([0.1, 1])))
```
> ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()

ping @NicolasHug 
