Port to actx.np.zeros #2384

Job	Run time
Examples Conda Py3	6m 44s
Documentation	4m 5s
Pytest Firedrake	6m 0s
Tests for downstream project grudge	10m 39s
Tests for downstream project pytential	50m 45s
Examples Firedrake	3m 15s
Mypy	3m 18s
Pylint	3m 34s
Tests for downstream project mirgecom	30s
Tests for downstream project mirgecom_examples	26s
Pytest Conda Py3	10m 33s
Ruff	6s
	1h 39m 55s

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