Use StarlarkCommandLineValueUnpack in add_hidden #5628

Job	Run time
Get the latest prelude hash	2s
build (ubuntu-22.04, aarch64-unknown-linux-gnu, true)	10m 27s
build (ubuntu-22.04, aarch64-unknown-linux-musl, true)	10m 6s
build (ubuntu-22.04, x86_64-unknown-linux-gnu)	9m 23s
build (ubuntu-22.04, x86_64-unknown-linux-musl, true)	10m 6s
build (macos-12, aarch64-apple-darwin, true)	18m 40s
build (macos-12, x86_64-apple-darwin)	13m 11s
build (windows-2022, x86_64-pc-windows-msvc, true)	19m 2s
Check if there's a release for this half of the month already	3s
Release `latest` tag	25s
Publish buck2.build	2m 1s
Release bi-monthly tag	0s
	1h 33m 26s

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