Update demo assets

[aatanasov-cloudinary]

Updated the demo assets with new ones:

• Image (to replace the flower): https://res.cloudinary.com/demo/image/upload/v1442827650/leather_bag.jpg
• Video (to replace the dog video): https://res.cloudinary.com/demo/video/upload/v1695197515/docs/sailing_boat.mp4

Approach

• Changed all references that used the previous demo assets.

QA notes

• Remove the cloudinary_media_display option from your local instance. (There will be a separate PR for the upgrade logic so users don't need to do that step)
• Review the following Cloudinary pages and ensure the new assets appear:
  • admin.php?page=cloudinary_image_settings
  • admin.php?page=cloudinary_video_settings
  • admin.php?page=cloudinary_lazy_loading
  • admin.php?page=cloudinary_responsive