Ensure Quote Block Borders are Visible Across All Color Variations and Sections

[alaminfirdows]

Description
Closes #653

This PR resolves the issue, and now the borders of quote blocks are displayed in all themes by removing the border color from theme.json.

Screenshots

Testing Instructions

1. Start by creating a new page or post.
2. Add a "Group" block and apply "Section Style 5" to it.
3. Within this group, insert a "Quote" block.
4. Preview the page or post.

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Co-authored-by: alaminfirdows <alaminfirdows@git.wordpress.org>
Co-authored-by: beafialho <beafialho@git.wordpress.org>
Co-authored-by: carolinan <poena@git.wordpress.org>
Co-authored-by: juanfra <juanfra@git.wordpress.org>

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Preview changes

You can preview these changes by following the link below:

• Preview changes for twentytwentyfive

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Note

The preview sites are created using WordPress Playground. You can add content, edit settings, and test the themes as you would on a real site, but please note that changes are not saved between sessions.

[beafialho]

Thank you for finding this one and submitting the PR.

I spotted two issues:

• Dusk: Styles 2, 4 and 5 aren't looking accessible (including the border)

dusk-quote.mp4

• Sunrise: Styles 1, 2, 3, 4 aren't looking accessible (including the border)

sunrise-quote.mp4

Not sure if this should to be addressed in this PR or another.

[carolinan]

I think this text color issue should be fixed in #619 since it already adjusts the color for several other blocks?

[juanfra]

As requested, I pushed a fix here.

[juanfra]

I'm closing this one as it was fixed in the other PR. Thanks for your contribution, I've added credits to all here.