Don't call QApplication.setQuitOnLastWindowClosed(False). (#1142) #1846

Job	Run time
build (ubuntu-latest, 3.8)	9m 11s
build (ubuntu-latest, 3.11)	16m 9s
build (windows-latest, 3.8)	10m 53s
build (windows-latest, 3.11)	11m 17s
build (macos-latest, 3.8)	6m 56s
build (macos-latest, 3.11)	8m 36s
build (windows-latest, 3.9)	6m 51s
build (ubuntu-latest, pypy-3.8)	4m 33s
build (macos-latest, 3.10)	8m 11s
check_release	2m 32s
link_check	2m 44s
Make SDist	30s
test_docs	2m 41s
Test Lint	1m 49s
Test Minimum Versions	2m 59s
Test Prereleases	1m 57s
test_without_debugpy (ubuntu-latest, 3.9)	6m 54s
Install from SDist and Test	7m 6s
coverage	0s
tests_check	2s
	1h 51m 51s

Provide feedback