fix(server): early exit in doc parse (#11507)

packages/backend/server/src/core/utils/blocksuite.ts

@@ -132,11 +132,12 @@ export function parsePageDoc(
         } else if (summaryLenNeeded > 0) {
           content.summary += text.toString();
           summaryLenNeeded -= text.length;
-        }
+        } else {
           break;
         }
       }
     }
+  }
 
   return content;
 }