remove deprecated ipyparallel methods now that they are broken anyway #2619

Job	Run time
build (ubuntu-latest, 3.9)	3m 5s
link_check	3m 23s
check_release	1m 37s
build (ubuntu-latest, 3.13)	3m 24s
build (windows-latest, 3.9)	9m 19s
Make SDist	28s
build (windows-latest, 3.13)	9m 6s
test_docs	38s
build (macos-latest, 3.9)	3m 7s
build (macos-latest, 3.13)	6m 0s
Test Lint	1m 5s
Test Minimum Versions	2m 19s
build (ubuntu-latest, pypy-3.9)	2m 55s
build (macos-latest, 3.10)	3m 11s
Test Prereleases	2m 2s
build (ubuntu-latest, 3.11)	3m 10s
test_without_debugpy (ubuntu-latest, 3.9)	1m 57s
build (ubuntu-latest, 3.12)	3m 28s
Install from SDist and Test	2m 13s
coverage	14s
tests_check	4s
	1h 2m 45s

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