[PM-14589] Prevent SSH key item creation

[SaintPatrck]

🎟️ Tracking

https://bitwarden.atlassian.net/browse/PM-14589

📔 Objective

Removed the SSH key feature flag and disabled the SSH key item type option in VaultAddEdit screen.

The SSH key item type option is currently hidden until the SDK supports it.

📸 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
• Used internationalization (i18n) for all UI strings
• CI builds passed
• Communicated to DevOps any deployment requirements
• Updated any necessary documentation 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 – 5cb670cc-110c-4b73-8f69-46768c8e5da1

No New Or Fixed Issues Found

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.04%. Comparing base (e397c03) to head (5f2d8c5).
Report is 18 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4251      +/-   ##
==========================================
- Coverage   89.05%   89.04%   -0.01%     
==========================================
  Files         445      445              
  Lines       38786    38770      -16     
  Branches     5422     5421       -1     
==========================================
- Hits        34539    34523      -16     
  Misses       2367     2367              
  Partials     1880     1880              

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