JS tipTip error on single product page of NON appointable products

[Valentina R]

On single product pages of non-appointable products, a JS error is produced from the addons.min.js file.

Can be simply reproduced on a simple product with or without addons configured.

Reported here: https://bookingwp.com/forums/topic/js-error-on-single-product-pages/

[Željan Topić]

Fixed with 4.2.9.2