🐛(y-provider) fix interlinking markdown test for blocknote 0.51.4

The 0.51.4 markdown serializer no longer emits the optional link title
attribute, so the exported link is `[text](url)` without ` "title"`. The
title is still present in the HTML export. Update the expectation to match.

Author: sylvinus

src/frontend/servers/y-provider/__tests__/convert.test.ts

@@ -472,8 +472,10 @@ describe('Conversion Testing', () => {
       .send(Buffer.from(yjsUpdate));
 
     expect(response.status).toBe(200);
+    // The markdown serializer keeps the link text and URL but drops the
+    // optional title attribute (still present in the HTML export).
     expect(response.text).toContain(
-      '[Other doc](http://localhost:3000/docs/00000000-0000-0000-0000-000000000123/ "Other doc")',
+      '[Other doc](http://localhost:3000/docs/00000000-0000-0000-0000-000000000123/)',
     );
   });