Fix time computation in CAGRA notebook #4348

Job	Run time
checks / other-checks	37s
checks / check-style	1m 37s
devcontainer / build (amd64, 12.2, conda)	2m 54s
devcontainer / build (amd64, 12.2, pip)	2m 59s
wheel-build-pylibraft / compute-matrix	6s
conda-cpp-build / compute-matrix	5s
conda-cpp-build / 11.8.0, 3.10, amd64, ubuntu22.04	13m 46s
conda-cpp-build / 12.2.2, 3.10, amd64, ubuntu22.04	3m 29s
conda-cpp-build / 11.8.0, 3.10, arm64, ubuntu22.04	13m 39s
conda-cpp-build / 12.2.2, 3.10, arm64, ubuntu22.04	3m 21s
wheel-build-pylibraft / 11.8.0, 3.9, amd64, centos7	2m 48s
wheel-build-pylibraft / 12.2.2, 3.9, amd64, centos7	2m 51s
wheel-build-pylibraft / 11.8.0, 3.10, amd64, centos7	2m 54s
wheel-build-pylibraft / 12.2.2, 3.10, amd64, centos7	2m 51s
wheel-build-pylibraft / 11.8.0, 3.11, amd64, centos7	2m 48s
wheel-build-pylibraft / 12.2.2, 3.11, amd64, centos7	2m 48s
wheel-build-pylibraft / 11.8.0, 3.9, arm64, rockylinux8	2m 46s
wheel-build-pylibraft / 12.2.2, 3.9, arm64, rockylinux8	2m 47s
wheel-build-pylibraft / 11.8.0, 3.10, arm64, rockylinux8	2m 55s
wheel-build-pylibraft / 12.2.2, 3.10, arm64, rockylinux8	2m 46s
wheel-build-pylibraft / 11.8.0, 3.11, arm64, rockylinux8	2m 52s
wheel-build-pylibraft / 12.2.2, 3.11, arm64, rockylinux8	2m 51s
wheel-tests-pylibraft	0s
wheel-build-raft-dask	0s
wheel-tests-raft-dask	0s
conda-cpp-checks	0s
conda-python-build	0s
conda-cpp-tests	0s
docs-build	0s
conda-python-tests	0s
pr-builder	0s
	1h 16m 30s

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