Add FXIOS-14030 [Settings] Export Nimbus DB when copying databases

[freshstrangemusic]

📜 Tickets

Jira ticket
Github issue

💡 Description

The Nimbus RKV database is now included when copying databases into user file storage.

🎥 Demos

Before	After

Demo

📝 Checklist

• I filled in the ticket numbers and a description of my work
• I updated the PR name to follow our PR naming guidelines
• I ensured unit tests pass and wrote tests for new code
• If working on UI, I checked and implemented accessibility (Dynamic Text and VoiceOver)
• If adding telemetry, I read the data stewardship requirements and will request a data review
• If adding or modifying strings, I read the guidelines and will request a string review from l10n
• If needed, I updated documentation and added comments to complex code

[mobiletest-ci-bot]

	Messages
📖	Project coverage: 37.91%

🧹 Tidy commit

Just 1 file(s) touched. Thanks for keeping it clean and review-friendly!

✅ Per-file coverage

All changed files meet the threshold of 35.0%.

Client.app: Coverage: 37.07

File	Coverage
ExportBrowserDataSetting.swift	0.0%	⚠️

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