CI: Make the downstream enterprise test a check instead of comments (#59071)

pkg/build/stringutil/contains.go

@@ -0,0 +1,10 @@
+package stringutil
+
+func Contains(arr []string, s string) bool {
+	for _, e := range arr {
+		if e == s {
+			return true
+		}
+	}
+	return false
+}