feat(core): highlight the share button (#12470)

close AF-2659
![CleanShot 2025-05-23 at 11 07 24@2x](https://github.com/user-attachments/assets/9d2047a8-4f84-40dd-8f0d-9d8a6abac616)

<!-- This is an auto-generated comment: release notes by coderabbit.ai -->

## Summary by CodeRabbit

- **Style**
  - Updated the share button to use the primary styling for improved visual emphasis.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/frontend/core/src/modules/share-menu/view/share-menu/share-menu.tsx

@@ -222,7 +222,7 @@ const DefaultShareButton = forwardRef(function DefaultShareButton(
           : t['com.affine.share-menu.option.link.no-access.description']()
       }
     >
-      <Button ref={ref} className={styles.button}>
+      <Button ref={ref} className={styles.button} variant="primary">
         <div className={styles.buttonContainer}>
           {shared ? <PublishIcon fontSize={16} /> : <LockIcon fontSize={16} />}
           {t['com.affine.share-menu.shareButton']()}