refactor(@angular-devkit/core): don't use concrete type as interface #1533

Job	Run time
lint	2m 2s
build	15s
e2e_windows (windows-2025, 22, npm, 1)	1m 30s
e2e_windows (windows-2025, 22, esbuild, 0)	40s
e2e_windows (windows-2025, 22, esbuild, 4)	49s
e2e_windows (windows-2025, 22, npm, 0)	1m 11s
e2e_windows (windows-2025, 22, esbuild, 5)	52s
e2e_windows (windows-2025, 22, esbuild, 2)	1m 28s
e2e_windows (windows-2025, 22, npm, 2)	53s
e2e_windows (windows-2025, 22, npm, 4)	51s
e2e_windows (windows-2025, 22, esbuild, 3)	40s
e2e_windows (windows-2025, 22, esbuild, 1)	1m 25s
e2e_windows (windows-2025, 22, npm, 3)	50s
e2e_windows (windows-2025, 22, npm, 5)	41s
e2e-snapshots	0s
e2e	0s
e2e-package-managers	0s
Browser Compatibility Tests	0s
test	0s
publish-snapshots	0s
	14m 7s

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