Fix the detection of the attach bbcode

See #6579

Author: dtdesign

ts/WoltLabSuite/Core/Component/Attachment/List.ts

@@ -172,7 +172,7 @@ function observeInsertedAttachments(element: HTMLElement, files: HTMLCollectionO
     embeddedAttachments.add(attachmentId);
   });
 
-  const bbcodeMatches = editor.element.innerText.matchAll(/\[attach=('\d+'|"\d+"|\d+)(?:,[^]]+?)?\]\[\/attach\]/g);
+  const bbcodeMatches = editor.element.innerText.matchAll(/\[attach=(?:'|")?(\d+)(?:'|")?(?:,[^]]+?)?\]\[\/attach\]/g);
   for (const match of bbcodeMatches) {
     const attachmentId = parseInt(match[1]);
     embeddedAttachments.add(attachmentId);