fix(angular): avoid forEach in classList

angular/src/directives/control-value-accessors/value-accessor.ts

@@ -54,10 +54,15 @@ function setIonicClasses(element: ElementRef) {
       'ion-pristine'
     );
 
-    classList.forEach((cls: string) => {
-      if (cls.startsWith('ng-')) {
-        classList.add(`ion-${cls.substr(3)}`);
+    for (let i = 0; i < classList.length; i++) {
+      const item = classList.item(i);
+      if (item && startsWith(item, 'ng-')) {
+        classList.add(`ion-${item.substr(3)}`);
       }
-    });
+    }
   });
 }
+
+function startsWith(input: string, search: string): boolean {
+  return input.substr(0, search.length) === search;
+}