Add empty string to `button_click` event

[Jack-Keene]

Many customers end up with lots of failed events related to the button_click schema because ‘label’ property is marked as required. However, many buttons don’t contain any inner text as they use icons or svgs instead. For example, nav bars, exit buttons, etc.

In these cases, all of these button_click events fail validation.

There is a workaround for the button_click tracking to attach ‘data-sp-button-label’ attribute to the button element. But this would require a lot of work on the engineering team to update all buttons with relevant labels.

It seems to be the better approach would be to add a default empty label and then they at least can capture the click event even if it doesn’t have a label.