Using token with external url to "onclick attribute on layout wrapper" throws InvalidArgumentException

If a view mode is set to have an onclick attribute, whose value comes from a token that gives an external url, an uncaught InvalidArgumentException is thrown.

This is happening because DS supposes that the token will return an internal uri, which is not always the case.

Example case: The entity has a link field, which has an external url in the link's value.

The problem is in ds.module @ line 561 :

      $url = Url::fromUri('internal:/' . $url);

This supposes that the $url will always be internal.

Steps to reproduce:

1. Create a link field to a node (or any other entity)
2. Create a node and type an external url to this field, for example https://www.drupal.org
3. Go to admin/structure/types/manage/YOUR_NODE_BUNDLE/display and select a Display Suite layout
4. At the Custom wrappers select Add link > Tokens and in the Custom link use your field token: [node:field_link:uri]

Now if you clear caches and try to visit your node, you will get a WSOD with InvalidArgumentException:

The website encountered an unexpected error. Please try again later.</br></br><em class="placeholder">InvalidArgumentException</em>: The internal path component &#039;https://www.drupal.org&#039; is external. You are not allowed to specify an external URL together with internal:/. in <em class="placeholder">Drupal\Core\Url::fromInternalUri()</em> (line <em class="placeholder">410</em> of <em class="placeholder">core/lib/Drupal/Core/Url.php</em>). <pre class="backtrace">Drupal\Core\Url::fromUri(&#039;internal:/https://www.drupal.org&#039;) (Line: 561)