MC-4232: Button text draggable triggers the image drop zones

- Fixed minor style issue

Author: Hwashiang Yu

app/code/Magento/PageBuilder/view/adminhtml/web/template/content-type/button-item/default/preview.html

@@ -14,7 +14,7 @@
        ko-style="data.link.style"
        css="data.link.css"
        click="function (context, event) { onClick($index(), event); }"
-       event="{dragstart: function(context, event) { event.preventDefault(); }}">
+       event="{ dragstart: function(context, event) { event.preventDefault(); }}">
         <span class="button-item-drag-handle" css="{disabled: parent.parent.children().length <= 1}"></span>
         <span attr="data.link_text.attributes"
               data-bind="liveEdit: { field: 'button_text', placeholder: buttonPlaceholder, selectAll: true }, hasFocusNoScroll: $parent.parent.preview.focusedButton() === $index()"