fix(lld): camera does not shut off when not scanning qr code

[LucasWerey]

✅ Checklist

• npx changeset was attached.
• Covered by automatic tests.
• Impact of the changes:
  • QR code scan

📝 Description

When "scan qr code" pop up on send flow is opened then closed the video stream isn't stopped.
To avoid this we cut off the stream once the pop up gets unmounted or if a qr code has been well scanned.

Before	After
https://github.com/LedgerHQ/ledger-live/assets/73439207/486a7eb3-8a7a-4c85-a762-5457f14113b4	https://github.com/LedgerHQ/ledger-live/assets/73439207/f9033832-70d8-4cc8-b8e8-2455472e66ae

❓ Context

• JIRA or GitHub link: LIVE-12938

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🧐 Checklist for the PR Reviewers

• The code aligns with the requirements described in the linked JIRA or GitHub issue.
• The PR description clearly documents the changes made and explains any technical trade-offs or design decisions.
• There are no undocumented trade-offs, technical debt, or maintainability issues.
• The PR has been tested thoroughly, and any potential edge cases have been considered and handled.
• Any new dependencies have been justified and documented.
• Performance considerations have been taken into account. (changes have been profiled or benchmarked if necessary)

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