Remove LoadInputDescriptions<TLoader> API #4263

Job	Run time
build-packages	5m 8s
build-solution (Debug, x64)	11m 8s
build-solution (Debug, arm64)	17m 8s
build-solution (Release, x64)	22m 43s
build-solution (Release, arm64)	21m 56s
verify-packages (net7.0)	2m 54s
verify-packages (net6.0)	9m 46s
verify-packages (net472)	2m 3s
run-tests-d3d12ma (net7.0)	6m 44s
run-samples (net7.0)	3m 29s
run-tests (net7.0)	7m 35s
run-tests-d3d12ma (net6.0)	6m 20s
run-tests-win2d (Debug, uwp)	4m 59s
run-samples (net6.0)	4m 26s
run-tests (net6.0)	8m 25s
run-tests-win2d (Debug, wasdk)	5m 5s
run-tests (net472)	8m 16s
run-samples (net472)	5m 21s
run-tests-win2d (Release, uwp)	10m 14s
run-samples-aot (x64)	8m 58s
run-tests-win2d (Release, wasdk)	6m 1s
run-samples-aot (arm64)	3m 40s
publish-nightlies-github	58s
publish-nightlies-azure-devops	40s
	3h 3m 57s

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