refactor(@angular/build): improve Vitest configuration merging #2318

Job	Run time
lint	2m 13s
build-e2e-windows	28s
build	29s
e2e-windows	0s
test	-1s
publish-snapshots	-1s
Browser Compatibility Tests	-1s
e2e	0s
e2e-package-managers	0s
e2e-snapshots	0s
	3m 7s

Provide feedback