Fix undefined link URL notice (and show non-links!)

Ref #242

web/themes/custom/agarica/agarica.theme

@@ -109,6 +109,7 @@ function agarica_languague_switch_link() {
   $links_render_array = [];
   // Transform the links to arrays that can be renderer.
   foreach ($links as $language => $link) {
+    if (isset($link['url'])) {
       $links_render_array[] = [
         '#type' => 'link',
         '#url' => $link['url'],
@@ -117,6 +118,13 @@ function agarica_languague_switch_link() {
           'language' => $link['language'],
         ],
       ];
+    } else {
+      // If there's no URL, we take only the title and don't try to make a link.
+      $links_render_array[] = [
+        '#type' => 'markup',
+        '#markup' => $link['title'],
+      ];
+    }
   }
 
   return $links_render_array;