fix(picker): include showBackdrop in interface

[brandyscarney]

fixes #18893

Pull request checklist

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• Tests for the changes have been added (for bug fixes / features)
• Docs have been reviewed and added / updated if needed (for bug fixes / features)
• Build (npm run build) was run locally and any changes were pushed
• Lint (npm run lint) has passed locally and any fixes were made for failures

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• Bugfix
• Feature
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What is the current behavior?

Issue Number: N/A

What is the new behavior?

Does this introduce a breaking change?

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• No

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