Aligns the core/code block border radius with core/image and core/quote blocks

[mhkuu]

Description

In #519, it was reported that the block border radius for core/code blocks did not match the core/image and core/quote blocks as per the Figma design. This PR fixes that. I've also made sure the Figma design is followed. I've removed the override in styles/ice.json as that did not change any of the styling anymore.

I kept the font family as it was in the default theme. I see Figma uses SF Mono, if we need to add that, perhaps it's better to do that in a separate PR?

Screenshots

Testing Instructions

1. Activate the theme.
2. Create a new post.
3. Add a code block, a quote block, and an image block. Set the image to be rounded.
4. Confirm the border radius of all of these blocks is the same.
5. In the site editor, set "icy" as your default theme.
6. Publish your post and check it in the front-end.
7. Confirm the code block still has the correct border radius.

Contributors

@mhkuu

Contributed during Yoast Contributor Day on Wednesday 4 October 2023.

Fixes #519.

[luminuu]

There are a couple more changes that need to be done besides the border radius, to make the code block look like in the design:

Link to Figma: https://www.figma.com/file/AlYr03vh4dVimwYwQkTdf6/Twenty-Twenty-Four?type=design&node-id=565-9988&mode=design&t=Pq7ws8UJuicCzyUb-4

Do you want to take a look at this and implement the changes in this PR too?

[mhkuu]

Sure @luminuu, I can continue working on this on Friday!

[mhkuu]

@luminuu Ready for review! 😸

[luminuu]

LGTM