[PM-14990] Add password prompt for ssh key import

[quexten]

🎟️ Tracking

https://bitwarden.atlassian.net/browse/PM-14990

📔 Objective

Adds a password prompt UI for importing password protected ssh keys in the desktop app.

📸 Screenshots

https://github.com/user-attachments/assets/fa66e14d-5556-4a1b-b54f-6d4fbb9cf964

⏰ 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[bot]]

Codecov Report

Attention: Patch coverage is 0% with 26 lines in your changes missing coverage. Please review.

Project coverage is 33.41%. Comparing base (38c4eeb) to head (2d85553). Report is 13 commits behind head on main.

:white_check_mark: All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
...ponents/dialog/sshkey-password-prompt.component.ts	0.00%	15 Missing :warning:
.../desktop/src/vault/app/vault/add-edit.component.ts	0.00%	10 Missing :warning:
libs/importer/src/components/dialog/index.ts	0.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #12105 +/- ## ========================================== - Coverage 33.44% 33.41% -0.03% ========================================== Files 2864 2872 +8 Lines 89637 89838 +201 Branches 17067 17107 +40 ========================================== + Hits 29978 30019 +41 - Misses 57297 57457 +160 Partials 2362 2362 ```

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