Make the validation test for entry-points work with Python 3.13+ #4379

Job	Run time
test_cygwin (39, windows-latest)	15m 52s
collateral (diffcov)	5m 58s
test (3.8, ubuntu-latest)	4m 8s
collateral (docs)	1m 59s
test (3.8, windows-latest)	11m 34s
collateral (check-extern)	14s
test (3.12, ubuntu-latest)	6m 1s
test (3.12, macos-latest)	5m 39s
test (3.12, windows-latest)	11m 55s
test (3.9, ubuntu-latest)	4m 13s
test (3.10, ubuntu-latest)	4m 10s
test (3.11, ubuntu-latest)	3m 56s
test (pypy3.10, ubuntu-latest, stdlib)	1h 15m 14s
test (ubuntu-latest, 3.10, stdlib)	3m 57s
test (3.8, macos-13)	6m 1s
integration-test	0s
check	1s
release	0s
	2h 40m 52s

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