PPL: Add `json_object` command #8412

Job	Run time
build-windows-macos (windows-latest, 21, -x doctest -PbuildPlatform=windows)	23m 47s
build-windows-macos (macos-13, 21)	39m 25s
Get-CI-Image-Tag / Get-CI-Image-Tag	7s
build-linux (21)	22m 54s
bwc-tests (21)	6m 47s
	1h 33m 0s

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