Remove overflow shadow in favor of border on readme

What does this MR do and why?

• Removes shadow on Read more button on personal readme
• Adds top border instead
• Add pointer cursor to row since whole thing is clickable (this should likely be improved in the future)
• Remove extra underline space on button hover

Why?

• If there's an image underneath the shadow, it looks pretty bad
• I originally switched to a dark box shadow instead of $white but it still looked kind of sloppy 🤷 A border provides the same delineation and looks cleaner

Screenshots or screen recordings

Before	After

How to set up and validate locally

• Look at user profile that is long enough to show Read more and also has an image where the button appears

Links

• ✂️ UX Paper Cuts 17.0 → Search and Filter (#444717 - closed)