chore: remove zenhub workflow #2643

Job	Run time
setup	1m 4s
test (app-dir/index.test.ts)	1m 33s
test (app-dir/rsc-basic.test.ts)	1m 31s
test (app-dir/next-font.test.ts)	1m 7s
test (app-dir/root-layout.test.ts)	1m 15s
test (app-dir/rendering.test.ts)	1m 31s
test (app-dir/app-middleware.test.ts)	1m 30s
test (app-dir/app-edge.test.ts)	1m 15s
test (app-dir/asset-prefix.test.ts)	1m 23s
test (app-dir/trailingslash.test.ts)	1m 27s
test (app-dir/with-babel.test.ts)	1m 25s
test (app-dir/async-component-preload.test.ts)	1m 12s
Report appDir e2e test results	8s
	16m 21s

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