[Chore] Upgrade file_picker to v11

[a-mabe]

Summary

file_picker has had a major version release. Update to support it.

Motivation

• Improves maintainability or readability
• Reduces technical debt
• Improves logging or diagnostics
• Improves consistency
• Removes unused or legacy code

Scope

• Upgrade to file_picker v11 and make sure nothing is broken.

Out of Scope

No response

Acceptance Criteria

• Behavior remains unchanged
• No new user-facing features
• No breaking changes
• Code is clearer or more consistent

Notes

No response