`ExperimentAxisQuery`: use `Experiment.context.threadpool` #1070

Job	Run time
setuptools (ubuntu-24.04)	10m 43s
SO copying (macos) TILEDB_EXISTS: no TILEDBSOMA_EXISTS: no	10m 4s
SO copying (docker) TILEDB_EXISTS: no TILEDBSOMA_EXISTS: no	10m 38s
Wheel from sdist (ubuntu-24.04)	8m 31s
setuptools (macos-latest)	8m 45s
SO copying (macos) TILEDB_EXISTS: yes TILEDBSOMA_EXISTS: no	11m 55s
SO copying (docker) TILEDB_EXISTS: yes TILEDBSOMA_EXISTS: no	10m 17s
Wheel from sdist (macos-latest)	11m 33s
SO copying (macos) TILEDB_EXISTS: yes TILEDBSOMA_EXISTS: yes	15m 52s
SO copying (docker) TILEDB_EXISTS: yes TILEDBSOMA_EXISTS: yes	10m 22s
	1h 48m 40s

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