Accordion Panel: Remove unnecessary wrapper div and simplify save

[himanshupathak95]

What?

Closes #71436

Removes the unnecessary accordion-content__wrapper div from the Accordion Panel block and simplifies the edit and save function.

Why?

The Accordion Panel block was generating redundant HTML markup with an extra wrapper div that served no functional purpose. There was also some complexity with the save function, with manual styling extraction.

How?

Replaced manual styling extraction with the standard useBlockProps.save() pattern that automatically handles all declared block supports (color, spacing, border, typography, shadow).

Testing Instructions

• Insert an Accordion block
• Add content to the Accordion Panel
• Apply various styling options like - Background colors, Text colors, Padding/margins, Borders, and border radius, Typography settings
• Save and view the post on the frontend
• Inspect the HTML output - verify there's no extra div
• Confirm all styling is still applied correctly to the main block wrapper

Screencasts

Before

Screen.Recording.2025-09-01.at.23.27.38.mp4

After

Screen.Recording.2025-09-01.at.23.22.28.mp4

[github-actions]

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Co-authored-by: himanshupathak95 <abcd95@git.wordpress.org>
Co-authored-by: t-hamano <wildworks@git.wordpress.org>

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[github-actions]

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[t-hamano]

Thanks for the PR! Can you update the Edit component as well as the save function?

[t-hamano]

LGTM! Nice cleanup 👍