Don't crash on invalid JSON in page_config (#1403) #2721

Job	Run time
check_release	2m 6s
Check Links	4m 17s
build (ubuntu-latest, 3.8)	5m 53s
build (ubuntu-latest, 3.11)	5m 31s
integration_check (ubuntu-latest, 3.8)	2m 18s
build (windows-latest, 3.8)	14m 1s
integration_check_pypy	2m 49s
integration_check (ubuntu-latest, 3.9)	2m 27s
build (windows-latest, 3.11)	13m 1s
Make SDist	31s
build (macos-latest, 3.8)	5m 55s
integration_check (ubuntu-latest, 3.10)	2m 25s
Test Docs	1m 10s
build (macos-latest, 3.11)	7m 54s
integration_check (ubuntu-latest, 3.11)	2m 14s
Test Examples	51s
build (windows-latest, 3.9)	10m 57s
Test Lint	54s
build (ubuntu-latest, pypy-3.8)	9m 55s
Test Minimum Versions	4m 26s
build (macos-latest, 3.10)	6m 19s
Test Prereleases	3m 49s
build (ubuntu-latest, 3.12)	6m 15s
Install from SDist and Test	4m 4s
coverage	17s
tests_check	3s
	2h 0m 22s

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