test: Adapt coefficients() logic for meta-estimators

[Schefflera-Arboricola]

followup for PR #1575

[github-actions]

Coverage Report for skore/

File	Stmts	Miss	Cover	Missing
venv/lib/python3.12/site-packages/skore
__init__.py	22	0	100%
_config.py	28	0	100%
exceptions.py	4	4	0%	4, 15, 19, 23
venv/lib/python3.12/site-packages/skore/persistence
__init__.py	0	0	100%
venv/lib/python3.12/site-packages/skore/persistence/item
__init__.py	55	1	98%	97
altair_chart_item.py	19	1	94%	14
item.py	22	1	95%	86
matplotlib_figure_item.py	36	1	97%	19
media_item.py	22	0	100%
numpy_array_item.py	27	1	96%	16
pandas_dataframe_item.py	29	1	96%	14
pandas_series_item.py	29	1	96%	14
pickle_item.py	22	0	100%
pillow_image_item.py	25	1	96%	15
plotly_figure_item.py	20	1	95%	14
polars_dataframe_item.py	27	1	96%	14
polars_series_item.py	22	1	95%	14
primitive_item.py	23	2	91%	13, 15
sklearn_base_estimator_item.py	29	1	96%	15
venv/lib/python3.12/site-packages/skore/persistence/repository
__init__.py	2	0	100%
item_repository.py	59	5	91%	15–16, 202–203, 226
venv/lib/python3.12/site-packages/skore/persistence/storage
__init__.py	4	0	100%
abstract_storage.py	22	0	100%
disk_cache_storage.py	33	1	96%	44
in_memory_storage.py	20	0	100%
venv/lib/python3.12/site-packages/skore/project
__init__.py	2	0	100%
project.py	83	2	97%	280, 392
venv/lib/python3.12/site-packages/skore/sklearn
__init__.py	6	0	100%
_base.py	171	14	91%	45, 58, 126, 129, 182, 185–186, 188–191, 224, 227–228
find_ml_task.py	61	0	100%
types.py	13	0	100%
venv/lib/python3.12/site-packages/skore/sklearn/_comparison
__init__.py	5	0	100%
metrics_accessor.py	173	3	98%	163, 316, 1294
report.py	67	1	98%	17
venv/lib/python3.12/site-packages/skore/sklearn/_cross_validation
__init__.py	5	0	100%
metrics_accessor.py	198	2	98%	318, 1088
report.py	110	2	98%	23, 431
venv/lib/python3.12/site-packages/skore/sklearn/_estimator
__init__.py	7	0	100%
feature_importance_accessor.py	143	2	98%	223–224
metrics_accessor.py	346	10	97%	174, 176, 183, 219, 249, 290, 317, 321, 336, 371
report.py	148	1	99%	24
venv/lib/python3.12/site-packages/skore/sklearn/_plot
__init__.py	2	0	100%
base.py	6	0	100%
style.py	28	0	100%
utils.py	122	5	95%	51, 75–77, 81
venv/lib/python3.12/site-packages/skore/sklearn/_plot/metrics
__init__.py	4	0	100%
precision_recall_curve.py	173	1	99%	660
prediction_error.py	164	0	100%
roc_curve.py	176	1	99%	649
venv/lib/python3.12/site-packages/skore/sklearn/train_test_split
__init__.py	0	0	100%
train_test_split.py	51	1	98%	16
venv/lib/python3.12/site-packages/skore/sklearn/train_test_split/warning
__init__.py	8	0	100%
high_class_imbalance_too_few_examples_warning.py	17	1	94%	80
high_class_imbalance_warning.py	18	0	100%
random_state_unset_warning.py	12	1	91%	15
shuffle_true_warning.py	10	1	90%	46
stratify_is_set_warning.py	12	1	91%	15
time_based_column_warning.py	23	2	91%	17, 73
train_test_split_warning.py	4	0	100%
venv/lib/python3.12/site-packages/skore/utils
__init__.py	6	0	100%
_accessor.py	52	2	96%	67, 108
_environment.py	27	0	100%
_fixes.py	8	0	100%
_index.py	5	0	100%
_logger.py	22	4	81%	15–17, 19
_measure_time.py	10	0	100%
_parallel.py	38	3	92%	23, 33, 124
_patch.py	13	5	61%	21, 23–24, 35, 37
_progress_bar.py	36	0	100%
_show_versions.py	33	0	100%
TOTAL	3219	89	97%

Tests	Skipped	Failures	Errors	Time
816	8 💤	0 ❌	0 🔥	54.514s ⏱️

[github-actions]

Documentation preview @ c921237

[auguste-probabl]

Thanks!