PyOpenCLActx: fixes to np.where, actx.to_numpy #2038

Job	Run time
Examples Conda Py3	1m 22s
Ruff	6s
Typos	4s
Documentation	1m 33s
Pytest Conda Py3 POCL	2m 41s
Tests for downstream project mirgecom_examples	6s
Tests for downstream project meshmode	10m 53s
Tests for downstream project grudge	12m 0s
Tests for downstream project mirgecom	6s
basedpyright	1m 31s
Pytest Conda Py3 Intel	2m 16s
	32m 38s

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