Tests

[MNT] Remove redundant `init`s in `OpenMLTask` descendants by adding ClassVar #2243

Job	Run time
docker	2s
(ubuntu-latest, Py3.8, sk0.23.1, sk-only:false)	2s
(windows-latest, Py, sk0.24.*, sk-only:false)	2s
(ubuntu-latest,Py3.10,sk1.5.*,sk-only:true)	3m 37s
(ubuntu-latest,Py3.11,sk1.4.*,sk-only:true)	1m 19s
(ubuntu-latest,Py3.11,sk1.7.*,sk-only:true)	3m 32s
(ubuntu-latest,Py3.12,sk1.6.*,sk-only:true)	1m 15s
(ubuntu-latest,Py3.13,sk1.5.*,sk-only:true)	2m 9s
(windows-latest,Py3.12,sk1.5.*,sk-only:false)	1h 19m 36s
(ubuntu-latest,Py3.10,sk1.4.*,sk-only:true)	1m 10s
(ubuntu-latest,Py3.14,sk1.5.*,sk-only:true)	4m 27s
(ubuntu-latest,Py3.10,sk1.7.*,sk-only:true)	1m 16s
(ubuntu-latest,Py3.13,sk1.6.*,sk-only:true)	2m 3s
(ubuntu-latest,Py3.14,sk1.7.*,sk-only:true)	1m 29s
(ubuntu-latest,Py3.11,sk1.6.*,sk-only:true)	2m 3s
(ubuntu-latest,Py3.12,sk1.5.*,sk-only:true)	2m 21s
(ubuntu-latest,Py3.14,sk1.7.*,sk-only:false)	3m 24s
(ubuntu-latest,Py3.10,sk1.3.*,sk-only:true)	1m 28s
(ubuntu-latest,Py3.12,sk1.5.,pd:2.,sk-only:false)	1h 15m 58s
(ubuntu-latest,Py3.10,sk1.6.*,sk-only:true)	2m 5s
(ubuntu-latest,Py3.12,sk1.5.*,sk-only:false)	3m 43s
(ubuntu-latest,Py3.11,sk1.5.*,sk-only:true)	3m 0s
(ubuntu-latest,Py3.13,sk1.7.*,sk-only:true)	1m 27s
(ubuntu-latest,Py3.12,sk1.4.*,sk-only:true)	1m 14s
(ubuntu-latest,Py3.11,sk1.3.*,sk-only:true)	2m 48s
(ubuntu-latest,Py3.14,sk1.6.*,sk-only:true)	4m 34s
(ubuntu-latest,Py3.12,sk1.7.*,sk-only:true)	1m 36s
(ubuntu-latest,Py3.12,sk1.3.*,sk-only:true)	1m 54s
	3h 29m 34s

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