Quote: Add border support

[aaronrobertshaw]

Part of: #43241

What?

Adopts border support for the Quote block.

Why?

• Offers greater design flexibility
• Improves consistency in design tooling with other blocks

How?

• Adopts all the available border block supports

Testing Instructions

• In the site editor, add a Quote block to a page
• Style via Global Styles and confirm the editor and frontend display correctly
• Override the global styles on the block instance and confirm they display appropriately in the editor and frontend

Screenshots or screencast

Screen.Recording.2024-07-15.at.1.00.24.PM.mp4

[andrewserong]

All testing nicely in the post and site editors, global styles, and overriding at the individual block level.

LGTM! 🚀

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[t-hamano]

It seems that when text alignment (center or right) is applied to this block, the theme style overrides the block-instance border, so the intended border is not applied. Do we need to reduce the CSS specificity of my theme style?

Below is a screenshot from Emptytheme:

[aaronrobertshaw]

Thanks for flagging that @t-hamano, I'll get a fix up for the theme styles shortly.

[aaronrobertshaw]

A quick fix for the theme alignment styles and plain block style is up in #64045.