Grid-search doesn't work with TableVectorizer

[LilianBoulard]

Describe the bug

A known bug introduced by #583 is that the TableVectorizer is not grid-searchable with sklearn on column_specific_transformers.
This is due to two things: first, the inheritance (something to do with set_params and get_params AFAIK), and second, the fact that we have None as default for transformer parameters (e.g. high_card_cat_transformer).
cc @glemaitre

#583 also introduced a new example that explained how to grid-search with the tool, and while the code is fine, it doesn't work due to the aforementioned issues. PR should reintroduce it (it's located in examples/FIXME/.

Steps/Code to Reproduce

from sklearn.model_selection import GridSearchCV
from sklearn.pipeline import make_pipeline
from sklearn.ensemble import HistGradientBoostingClassifier
from skrub import GapEncoder, TableVectorizer, MinHashEncoder
from skrub.datasets import fetch_employee_salaries

dataset = fetch_employee_salaries()

pipeline = make_pipeline(
    TableVectorizer(
        high_card_cat_transformer=GapEncoder(),
        specific_transformers=[
            ("mh_dep_name", MinHashEncoder(), ["department_name"]),
        ],
    ),
    HistGradientBoostingClassifier(),
)

params = {
    "tablevectorizer__high_card_cat_transformer__n_components": [10, 30, 50],
    "tablevectorizer__mh_dep_name__n_components": [25, 50],
}

grid_search = GridSearchCV(pipeline, param_grid=params)

grid_search.fit(dataset.X, dataset.y)

Expected Results

No error is thrown, the parameters are applied to the nested transformers.

Actual Results

ValueError: Invalid parameter 'mh_dep_name' for estimator TableVectorizer(high_card_cat_transformer=GapEncoder(),
                specific_transformers=[('mh_dep_name', MinHashEncoder(),
                                        ['department_name'])]). Valid parameters are: ['auto_cast', 'cardinality_threshold', 'datetime_transformer', 'high_card_cat_transformer', 'impute_missing', 'low_card_cat_transformer', 'n_jobs', 'numerical_transformer', 'remainder', 'sparse_threshold', 'specific_transformers', 'transformer_weights', 'verbose'].

Versions

Main branch, commit b2b3a7cafafe09431568e25570fa69431efafd51

[Vincent-Maladiere]

Closed by #814