add button to close prop modal on mobile

[cdt-eth]

Before

Whenever I open a prop on mobile it takes up the entire view, therefore I can't get out of it to go and read another prop. On desktop, I know you can just click outside of the modal to close it, but there's no spare room "outside" the modal to click. Also, since we don't change paths I can't just hit "Back" so I'm stuck and have to refresh the page.

After

By adding an "x" button on mobile, we can close the modal and avoid a "dead end."

[vercel[bot]]

@cdt-eth is attempting to deploy a commit to the personae labs Team on Vercel.

A member of the Team first needs to authorize it.

[lsankar4033]

lgtm, but @salvinoarmati defer to you on styling