Change allowed return type of Ember helper function to any (#25183)

types/ember/index.d.ts

@@ -3461,7 +3461,7 @@ declare module '@ember/component/helper' {
      * });
      * ```
      */
-    export function helper(helperFn: (params: any[], hash?: any) => string): any;
+    export function helper(helperFn: (params: any[], hash?: any) => any): any;
 }
 
 declare module '@ember/component/text-area' {

types/ember/test/helper.ts

@@ -33,3 +33,9 @@ function typedHelp(/*params, hash*/) {
 }
 
 export default helper(typedHelp);
+
+function arrayNumHelp(/*params, hash*/) {
+  return [1, 2, 3];
+}
+
+helper(arrayNumHelp);