Build against JupyterLab 4.1, fix tests #1700

Job	Run time
jstest/lint (ubuntu, >=20,<21, >=4.1.0,<5.0.0a0, >=4)	5m 9s
build (ubuntu, >=20,<21, >=4.1.0,<5.0.0a0, >=4)	4m 56s
smoke source install ubuntu py3.8 lab>=4.1.0,<5	1m 54s
smoke source install ubuntu py3.11 lab>=4.1.0,<5	1m 52s
atest ubuntu py3.8 r>=4	37m 27s
atest ubuntu py3.11 r>=4	39m 50s
atest macos py3.8 r>=4	47m 17s
atest macos py3.11 r>=4	1h 2m 21s
atest windows py3.8 r>=4	14m 9s
atest windows py3.11 r>=4	12m 7s
smoke ubuntu py3.8	35s
smoke ubuntu py3.11	29s
smoke ubuntu pypypy-3.8	1m 26s
smoke macos py3.8	1m 5s
smoke macos py3.11	44s
smoke macos pypypy-3.8	53s
smoke windows py3.8	1m 37s
smoke windows py3.11	1m 40s
smoke windows pypypy-3.8	6m 36s
	4h 2m 7s

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