refactor(@angular/build): use `ngHmrMode` define for Vite prebundling #915

Job	Run time
list	27s
workflow (build-cli)	1m 25s
workflow (modules-builder-tests)	1m 43s
workflow (build-unit-tests)	2m 10s
workflow (devkit-core-tests)	1m 10s
workflow (devkit-core-tests-rerun)	1m 16s
	8m 11s

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