Keras Documentation: Docstring examples for SKLearnClassifier and SKLearnRegressor do not work

The examples in the docstrings for SKLearnClassifier and SKLearnRegressor are currently not working. This is because of several small issues: - General issues: - Importing layers from keras.src.layers instead of keras.layers - Importing Model from keras.src.layers instead of keras.models - Unnecessary usage of [] around the output layer - SKLearnClassifier docstring issue: - The example uses n_classes=3, but this leads to a scikit-learn error: ValueError: n_classes(3) * n_clusters_per_class(2) must be smaller or equal 2**n_informative(2)=4 - SKLearnRegressor docstring issue: - Uses softmax activation where linear would be more appropriate (regression problem that does not fall between [0, 1]), causing warnings.

I will open a PR to address these issues shortly.