Global Styles: Prevent Unwanted ItemGroup List Rendering in Border Panel

[im3dabasia]

Part of: #67425

What?

Revised <ItemGroup> to use role="none" and prevent it from rendering an unnecessary role="list" when it is not semantically required.

Why?

Avoids adding unwanted list roles where a semantic list is not necessary, ensuring accessibility standards are maintained without enforcing unnecessary constraints.

How?

Updated <ItemGroup> to include role="none" and an optional as prop for flexibility. Removed instances of role="list" where a list structure wasn't required.

Testing Instructions

1. Add a new post.
2. Add a block, such as a button, that includes shadow support.
3. Inspect the "Drop Shadow" section of the button and observe the rendered ItemsGroup element.
4. Validate that the UI behavior and appearance remain unchanged.

Screenshots or screencast

Before

After

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