Tests

[MNT] Remove redundant `init`s in `OpenMLTask` descendants by adding ClassVar #2245

Job	Run time
docker	5s
(ubuntu-latest, Py3.8, sk0.23.1, sk-only:false)	4s
(windows-latest, Py, sk0.24.*, sk-only:false)	2s
(ubuntu-latest,Py3.10,sk1.4.*,sk-only:true)	1m 7s
(ubuntu-latest,Py3.10,sk1.5.*,sk-only:true)	1m 10s
(ubuntu-latest,Py3.10,sk1.3.*,sk-only:true)	1m 23s
(ubuntu-latest,Py3.10,sk1.7.*,sk-only:true)	1m 0s
(ubuntu-latest,Py3.11,sk1.6.*,sk-only:true)	1m 12s
(ubuntu-latest,Py3.11,sk1.3.*,sk-only:true)	1m 0s
(ubuntu-latest,Py3.12,sk1.3.*,sk-only:true)	8m 15s
(ubuntu-latest,Py3.11,sk1.4.*,sk-only:true)	1m 12s
(ubuntu-latest,Py3.14,sk1.7.*,sk-only:false)	1h 38m 39s
(ubuntu-latest,Py3.11,sk1.7.*,sk-only:true)	1m 13s
(ubuntu-latest,Py3.11,sk1.5.*,sk-only:true)	1m 9s
(ubuntu-latest,Py3.12,sk1.7.*,sk-only:true)	1m 16s
(ubuntu-latest,Py3.14,sk1.5.*,sk-only:true)	4m 48s
(ubuntu-latest,Py3.13,sk1.7.*,sk-only:true)	1m 13s
(ubuntu-latest,Py3.12,sk1.5.,pd:2.,sk-only:false)	6m 11s
(ubuntu-latest,Py3.14,sk1.6.*,sk-only:true)	4m 13s
(ubuntu-latest,Py3.14,sk1.7.*,sk-only:true)	1m 13s
(ubuntu-latest,Py3.10,sk1.6.*,sk-only:true)	1m 12s
(ubuntu-latest,Py3.12,sk1.4.*,sk-only:true)	1m 11s
(ubuntu-latest,Py3.12,sk1.5.*,sk-only:true)	1m 10s
(windows-latest,Py3.12,sk1.5.*,sk-only:false)	1h 26m 19s
(ubuntu-latest,Py3.12,sk1.5.*,sk-only:false)	1h 40m 19s
(ubuntu-latest,Py3.12,sk1.6.*,sk-only:true)	1m 9s
(ubuntu-latest,Py3.13,sk1.5.*,sk-only:true)	3m 40s
(ubuntu-latest,Py3.13,sk1.6.*,sk-only:true)	1m 19s
	5h 32m 44s

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