fix(catalog): CATALOG-2913 address STOCK_LEVEL_DISPLAY_SHOW_WHEN_LOW

    setting for skus. We were not properly switching back and forth
    between skus that were above and below their own respective
    threshholds.

assets/js/theme/common/product-details.js

@@ -463,6 +463,9 @@ export default class ProductDetails {
             // if the stock container is hidden, show
             viewModel.stock.$container.removeClass('u-hiddenVisually');
 
+            viewModel.stock.$input.text(data.stock);
+        } else {
+            viewModel.stock.$container.addClass('u-hiddenVisually');
             viewModel.stock.$input.text(data.stock);
         }