fix(ViewUtil): Removing FormattedString throw

When removing the children from a Label and one of these children is
a FormattedString, the FormattedTextProperty throw this exception:
"TypeError: Cannot read property 'textTransform' of undefined"

Author: m-abs

nativescript-angular/view-util.ts

@@ -265,6 +265,8 @@ export class ViewUtil {
         } else if (child.nodeName === "DetachedContainer") {
             // Skip - DetachedContainer is... well detached from its parent
             // Used with ListViews and other TemplatedItemsComponent views.
+        } else if (child.nodeName === "FormattedString") {
+            // Removing FormattedString and its Spans from a Label throws an exception
         } else if (isView(parent)) {
             parent._removeView(child);
         }