Cleanup dependencies

[Hinton]

🎟️ Tracking

📔 Objective

Removes some unnecessary dependencies from bitwarden-auth.

• serde_json only used in tests.
• serde_qs never used.
• serde_urlencoded replaced manual form handling with the .form method from reqwest.

Changed bitwarden-uniffi-error to be optional and removed uniffi as a dependency from it.

⏰ 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 – 8a30efa2-daba-4cf0-a981-fc1c199a6e50

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

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 78.27%. Comparing base (e30f1ea) to head (6ce9c1f).
⚠️ Report is 5 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #466      +/-   ##
==========================================
+ Coverage   78.25%   78.27%   +0.01%     
==========================================
  Files         275      275              
  Lines       27447    27438       -9     
==========================================
- Hits        21479    21476       -3     
+ Misses       5968     5962       -6     

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[JaredSnider-Bitwarden]

BW auth crate changes look good to me. Thank you for the clean up!