do not setup node/yarn when not needed #9487

Job	Run time
test-devcontainer	16m 41s
build-compiler (ubuntu-24.04, ocaml-variants.5.3.0+options,ocaml-option-static, true, true, linux...	7m 50s
build-compiler (ubuntu-24.04, ocaml-variants.5.0.0+options,ocaml-option-static, linux-x64, x86_64...	7m 44s
build-compiler (macos-15, 5.3.0, true, darwin-arm64, aarch64-apple-darwin)	11m 8s
build-compiler (macos-15-intel, 5.3.0, true, darwin-x64, x86_64-apple-darwin)	19m 35s
build-compiler (windows-2025, 5.3.0, true, win32-x64, x86_64-pc-windows-gnu, .exe)	17m 4s
build-compiler (ubuntu-24.04-arm, ocaml-variants.5.3.0+options,ocaml-option-static, true, true, t...	8m 13s
pkg-pr-new	56s
api-docs	12s
test-installation-npm (macos-15-intel)	26s
test-installation-npm (windows-2025)	1m 1s
test-installation-npm (ubuntu-24.04)	16s
test-integration-rewatch (macos-15)	3m 36s
test-installation-npm (ubuntu-24.04-arm)	17s
test-integration-rewatch (windows-2025)	7m 3s
test-integration-rewatch (macos-15-intel)	6m 20s
test-installation-pnpm (ubuntu-24.04-arm)	17s
test-installation-npm (macos-15)	15s
test-installation-pnpm (ubuntu-24.04)	12s
test-integration-rewatch (ubuntu-24.04-arm)	2m 53s
test-integration-rewatch (ubuntu-24.04)	3m 19s
test-installation-pnpm (macos-15-intel)	27s
test-installation-pnpm (macos-15)	18s
test-installation-pnpm (windows-2025)	28s
publish	0s
	1h 56m 31s

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