Unsplash: use framer-spinner class

[madebyisaacr]

Description

This pull request replaces the spinner component in Unsplash with the built-in framer-spinner class. This change also makes the image loading spinner smaller to match other spinners in Framer, but if there's a reason to use the larger spinner size, that can be changed.

Changelog

• Updated loading spinner style.

Testing

• Insert an image and look at the spinner. Verify that the spinner is white in both light and dark themes.
• Click the random image button and look at the spinner