PM-16900: Update form card style for auth

[matt-livefront]

🎟️ Tracking

PM-16900

📔 Objective

Updates the card style background within the auth views.

📸 Screenshots

Before	After

⏰ 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

[codecov]

Codecov Report

Attention: Patch coverage is 96.97987% with 9 lines in your changes missing coverage. Please review.

Project coverage is 89.58%. Comparing base (9242299) to head (325a842).
Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
BitwardenShared/UI/Auth/Landing/LandingView.swift	90.32%	3 Missing ⚠️
...I/Auth/Login/TwoFactorAuth/TwoFactorAuthView.swift	84.21%	3 Missing ⚠️
BitwardenShared/UI/Auth/Login/LoginView.swift	89.47%	2 Missing ⚠️
...Auth/SetMasterPassword/SetMasterPasswordView.swift	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1326      +/-   ##
==========================================
- Coverage   89.60%   89.58%   -0.02%     
==========================================
  Files         749      749              
  Lines       46977    46967      -10     
==========================================
- Hits        42092    42077      -15     
- Misses       4885     4890       +5     

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[github-actions]

Checkmarx One – Scan Summary & Details – 7dee766c-74af-42c9-9116-49d87099b600

Great job, no security vulnerabilities found in this Pull Request