Fix rate limiting in sphinx link checker #2256

Job	Run time
PhotonClient Build	39s
Photonlib - Build Examples - windows-2022	4m 57s
Gradle Build	3m 42s
Photonlib - Build Examples - macos-14	5m 15s
Photonlib - Build Examples - ubuntu-22.04	5m 0s
Build Offline Docs	36s
Photonlib - Build Docker - Athena	5m 1s
Photonlib - Build Docker - Raspbian	5m 1s
Photonlib - Build Host - Win64	4m 57s
Photonlib - Build Docker - Aarch64	4m 59s
Photonlib - Build Host - macOS	5m 12s
Photonlib - Build Host - Linux	5m 12s
Build Vendor JSON	38s
Build fat JAR - ${{ matrix.artifact-name }}	0s
smoketest-${{ matrix.image_suffix }}	0s
run-smoketest-native	0s
Build image - ${{ matrix.image_url }}	0s
Combine	1s
release	1s
dispatch	1s
	51m 12s

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