Revert use of new Lanczos solver in spectral clustering #5304

Job	Run time
devcontainer / amd64, 12.5, conda	7m 17s
changed-files / Check changed files	11s
checks / other-checks	37s
devcontainer / amd64, 12.5, pip	7m 17s
checks / check-style	2m 18s
conda-cpp-build	0s
wheel-build-pylibraft	0s
conda-python-build	0s
conda-cpp-tests	0s
conda-cpp-checks	0s
wheel-tests-pylibraft	0s
docs-build	0s
conda-python-tests	0s
wheel-build-raft-dask	0s
wheel-tests-raft-dask	0s
pr-builder / run	1s
	17m 41s

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