Delete associated thumbnail image when article is deleted (server-side)

[happychuks]

When an article is deleted, the associated thumbnail image is not removed from the file system. This can lead to orphaned images and unnecessary storage usage.

thumbnail images are saved in the media directory while in-content images are saved in the media/images directory

Expected behavior:
When an article is deleted, the associated thumbnail image should also be deleted from the file system.

Steps to reproduce:

• Create a new article with a thumbnail image.
• Delete the article.
• Verify that the thumbnail image still exists in the file system.