Fix rate limiting in sphinx link checker #2255

Job	Run time
PhotonClient Build	41s
Photonlib - Build Examples - windows-2022	11m 52s
Gradle Build	3m 45s
Photonlib - Build Examples - macos-14	6m 16s
Build Offline Docs	52s
Photonlib - Build Examples - ubuntu-22.04	8m 1s
Photonlib - Build Docker - Athena	5m 32s
Photonlib - Build Host - Win64	11m 20s
Photonlib - Build Docker - Raspbian	5m 58s
Photonlib - Build Host - macOS	7m 8s
Photonlib - Build Docker - Aarch64	6m 26s
Photonlib - Build Host - Linux	7m 12s
Build Vendor JSON	41s
Build fat JAR - Win64	5m 24s
Build fat JAR - macOS	5m 14s
Build fat JAR - macOSArm	5m 12s
Build fat JAR - Linux	2m 14s
Build fat JAR - LinuxArm64	2m 6s
smoketest-RaspberryPi	1m 12s
run-smoketest-native (ubuntu-22.04, jar-Linux, -Djdk.lang.Process.launchMechanism=vfork)	13s
run-smoketest-native (windows-latest, jar-Win64)	22s
Build image - ${{ matrix.image_url }}	0s
run-smoketest-native (macos-latest, jar-macOS, x64)	16s
Combine	0s
release	0s
dispatch	0s
	1h 37m 57s

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