build: remove legacy rnjs setup #939

Job	Run time
list	27s
workflow (devkit-core-tests)	1m 18s
workflow (devkit-core-tests-rerun)	1m 11s
workflow (modules-builder-tests)	1m 44s
workflow (build-cli)	1m 27s
workflow (build-unit-tests)	2m 15s
	8m 22s

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