feat: Restore backup from Settings - WPB-11718

[KaterinaWire]

WPB-11718 [iOS] Move backup import from login flow to settings

Issue

This PR introduces the functionality to restore a backup from settings. All logic is in the WireUI.

This includes:

• removing backup restore from the login flow
• refactoring SessionManager methods for backup restore
• providing UI and error handling
• snapshot tests

Testing

Settings -> Account -> Backup or Restore -> Restore from backup

Checklist

• Title contains a reference JIRA issue number like [WPB-XXX].
• Description is filled and free of optional paragraphs.
• Adds/updates automated tests.

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UI accessibility checklist

If your PR includes UI changes, please utilize this checklist:

• Make sure you use the API for UI elements that support large fonts.
• All colors are taken from WireDesign.ColorTheme or constructed using WireDesign.BaseColorPalette.
• New UI elements have Accessibility strings for VoiceOver.

[github-actions]

Test Results

    2 files     11 suites   2m 4s ⏱️
1 866 tests 1 838 ✅ 27 💤 1 ❌
1 877 runs  1 849 ✅ 27 💤 1 ❌

For more details on these failures, see this check.

Results for commit e09f5af.

♻️ This comment has been updated with latest results.

[datadog-wireapp]

Datadog Report

Branch report: feat/restore-backup-WPB-11718
Commit report: f689bde
Test service: wire-ios-mono

✅ 0 Failed, 1758 Passed, 27 Skipped, 1m 56.62s Total Time