refactor(@schematics/angular): remove third-party typescript copy #3483

Job	Run time
list	49s
workflow (modules-builder-tests)	1m 57s
workflow (devkit-core-tests-rerun)	1m 48s
workflow (build-cli)	1m 55s
workflow (build-unit-tests)	2m 21s
workflow (devkit-core-tests)	1m 19s
	10m 9s

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