Fix failing isophote test for scipy 1.15 #2437

Job	Run time
ubuntu-latest, py311-test-oldestdeps	3m 10s
ubuntu-latest, py311-test-alldeps	3m 8s
ubuntu-latest, py312-test-alldeps-cov	6m 54s
macos-latest, py312-test-alldeps	2m 21s
M1 macos-14, py312-test-alldeps	2m 23s
windows-latest, py312-test-alldeps	4m 22s
ubuntu-latest, py312-test	5m 8s
ubuntu-latest, codestyle	19s
ubuntu-latest, pep517	20s
ubuntu-latest, bandit	23s
ubuntu-latest, py313-test-alldeps	3m 26s
(Allowed failure) ubuntu-latest, py313-test-devdeps	6m 6s
	38m 0s

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