Build against JupyterLab 4.1, fix tests #1710

Job	Run time
build (ubuntu, >=20,<21, >=4.1.0,<5.0.0a0, >=4)	2m 49s
jstest/lint (ubuntu, >=20,<21, >=4.1.0,<5.0.0a0, >=4)	5m 10s
smoke source install ubuntu py3.8 lab>=4.1.0,<5	1m 51s
atest ubuntu py3.8 r>=4	29m 45s
smoke source install ubuntu py3.11 lab>=4.1.0,<5	1m 50s
atest ubuntu py3.11 r>=4	29m 0s
atest macos py3.8 r>=4	38m 56s
atest macos py3.11 r>=4	36m 9s
atest windows py3.8 r>=4	39m 6s
atest windows py3.11 r>=4	38m 16s
smoke ubuntu py3.8	38s
smoke ubuntu py3.11	36s
smoke ubuntu pypypy-3.8	1m 40s
smoke macos py3.8	55s
smoke macos py3.11	45s
smoke macos pypypy-3.8	52s
smoke windows py3.8	1m 21s
smoke windows py3.11	1m 27s
smoke windows pypypy-3.8	4m 15s
	3h 55m 21s

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