Center big play button in video divs

[bruvellu]

Description

This PR fixes the uncentered play button in videos rendered from cross-reference divs by adding a missing style class.

Addresses #13411.

Checklist

I have (if applicable):

• filed a contributor agreement.
• referenced the GitHub issue this PR closes
• updated the appropriate changelog in the PR
• ensured the present test suite passes
• added new tests
• created a separate documentation PR in Quarto's website repo and linked it to this PR

[posit-snyk-bot]

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[cscheid]

Thank you! Can you add a changelog entry to news/changelog-1.9.md? You can use https://github.com/quarto-dev/quarto-cli/blob/main/news/changelog-1.8.md as an example.

[cscheid]

I don't think we need a contributor agreement for a small change like this, although we'd love for you to send one so you're ready when you make a larger PR!

[bruvellu]

Thank you! Can you add a changelog entry to news/changelog-1.9.md? You can use https://github.com/quarto-dev/quarto-cli/blob/main/news/changelog-1.8.md as an example.

Done!

I don't think we need a contributor agreement for a small change like this, although we'd love for you to send one so you're ready when you make a larger PR!

Cool, I'll check the agreement

[cscheid]

Merged! I'll make a few minor changes so we don't forget to acknowledge you in the next release. Thanks for the contribution, we very much appreciate it! 🎉

[bruvellu]

Thanks! Will the original issue be automatically closed upon the 1.9 release?

[cscheid]

We close them right away, and often automatically. I thought "addresses #number" worked in github, but it doesn't. I'll do it now. Thanks for the reminder.