PM-27149: Update empty vault illustration

[david-livefront]

🎟️ Tracking

PM-27149

📔 Objective

This PR updates the illustrations in the Authenticator app to match the styles and color theme of the Password Manager.

📸 Screenshots

Before	After
before.mp4	after.mp4

⏰ Reminders before review

• Contributor guidelines followed
• All formatters and local linters executed and passed
• Written new unit and / or integration tests where applicable
• Protected functional changes with optionality (feature flags)
• Used internationalization (i18n) for all UI strings
• CI builds passed
• Communicated to DevOps any deployment requirements
• Updated any necessary documentation (Confluence, contributing docs) or informed the documentation team

🦮 Reviewer guidelines

• 👍 (:+1:) or similar for great changes
• 📝 (:memo:) or ℹ️ (:information_source:) for notes or general info
• ❓ (:question:) for questions
• 🤔 (:thinking:) or 💭 (:thought_balloon:) for more open inquiry that's not quite a confirmed issue and could potentially benefit from discussion
• 🎨 (:art:) for suggestions / improvements
• ❌ (:x:) or ⚠️ (:warning:) for more significant problems or concerns needing attention
• 🌱 (:seedling:) or ♻️ (:recycle:) for future improvements or indications of technical debt
• ⛏ (:pick:) for minor or nitpick changes

[github-actions]

Checkmarx One – Scan Summary & Details – d3397532-3379-4344-94fc-26dba4d7716f

Great job! No new security vulnerabilities introduced in this pull request

[david-livefront]

Thanks @SaintPatrck

[codecov]

Codecov Report

❌ Patch coverage is 83.33333% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 84.80%. Comparing base (97bb93c) to head (d8b662e).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...arden/authenticator/ui/auth/unlock/UnlockScreen.kt	0.00%	1 Missing ⚠️
...tor/ui/platform/feature/tutorial/TutorialScreen.kt	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6059      +/-   ##
==========================================
+ Coverage   84.76%   84.80%   +0.03%     
==========================================
  Files         736      719      -17     
  Lines       55340    54932     -408     
  Branches     7632     7628       -4     
==========================================
- Hits        46909    46585     -324     
+ Misses       5763     5680      -83     
+ Partials     2668     2667       -1     

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