PPL: Add `json_object` command #8467

Job	Run time
build-windows-macos (windows-latest, 21, -x doctest -PbuildPlatform=windows)	23m 55s
build-windows-macos (macos-13, 21)	37m 28s
Get-CI-Image-Tag / Get-CI-Image-Tag	4s
bwc-tests (21)	6m 37s
build-linux (21)	31m 50s
	1h 39m 54s

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