MC-3903: Clicking into live edit shouldn't focus all text if existing text is present

- enable selectAll text for Button Item

Author: anthoula

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

@@ -9,6 +9,6 @@
     <render args="getOptions().template" />
     <a attr="data.link.attributes" ko-style="data.link.style" css="data.link.css">
         <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 }, hasFocus: $parent.parent.preview.isLiveEditing() === $index()" event="{ focusout: onFocusOut.call($data) }"></span>
+        <span attr="data.link_text.attributes" data-bind="liveEdit: { field: 'button_text', placeholder: buttonPlaceholder, selectAll: true }, hasFocus: $parent.parent.preview.isLiveEditing() === $index()" event="{ focusout: onFocusOut.call($data) }"></span>
     </a>
 </div>