Fallback to url if text is disabled (#15830)

* Fallback to url if text is disabled

Fix `htmlspecialchars(): Argument #1 ($string) must be of type string, null given`

* Update models/Document/Editable/Link.php

Readable code

Co-authored-by: Divesh Pahuja <divesh.pahuja@pimcore.com>

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Co-authored-by: Divesh Pahuja <divesh.pahuja@pimcore.com>

models/Document/Editable/Link.php

@@ -171,7 +171,12 @@ public function frontend()
 
             $attribs = array_unique($attribs);
 
-            return '<a href="'.$url.'" '.implode(' ', $attribs).'>' . $prefix . ($noText ? '' : htmlspecialchars($disabledText ? $url : $this->data['text'])) . $suffix . '</a>';
+            $text = '';
+            if (!$noText) {
+                $text = htmlspecialchars($disabledText ? $url : ($this->data['text'] ?? $url));
+            }
+
+            return '<a href="'.$url.'" '.implode(' ', $attribs).'>' . $prefix . $text . $suffix . '</a>';
         }
 
         return '';