Remove last remaining rescript-legacy usage #9293

Job	Run time
build-compiler (macos-15-intel, 5.3.0, true, darwin-x64, x86_64-apple-darwin)	10m 38s
build-compiler (macos-15, 5.3.0, true, darwin-arm64, aarch64-apple-darwin)	3m 48s
build-compiler (windows-2025, 5.3.0, true, win32-x64, x86_64-pc-windows-gnu, .exe)	6m 16s
build-compiler (ubuntu-24.04, ocaml-variants.5.3.0+options,ocaml-option-static, true, true, linux...	3m 1s
build-compiler (ubuntu-24.04-arm, ocaml-variants.5.3.0+options,ocaml-option-static, true, true, t...	3m 47s
build-compiler (ubuntu-24.04, ocaml-variants.5.0.0+options,ocaml-option-static, linux-x64, x86_64...	2m 42s
api-docs	1m 37s
pkg-pr-new	51s
test-integration-rewatch (ubuntu-24.04-arm)	1m 10s
test-integration-rewatch (macos-15-intel)	2m 44s
test-installation-pnpm (macos-15-intel)	26s
test-integration-rewatch (macos-15)	1m 37s
test-installation-pnpm (macos-15)	17s
test-installation-pnpm (windows-2025)	33s
test-installation-pnpm (ubuntu-24.04)	13s
test-installation-npm (macos-15-intel)	28s
test-integration-rewatch (ubuntu-24.04)	1m 19s
test-installation-pnpm (ubuntu-24.04-arm)	16s
test-integration-rewatch (windows-2025)	3m 2s
test-installation-npm (ubuntu-24.04-arm)	19s
test-installation-npm (ubuntu-24.04)	16s
test-installation-npm (macos-15)	17s
test-installation-npm (windows-2025)	1m 10s
publish	-1s
	46m 46s

Provide feedback