[PM-12400] Add private key regeneration SDK methods

[Thomas-Avery]

🎟️ Tracking

https://bitwarden.atlassian.net/browse/PM-12400

📔 Objective

Add shared methods to enable private key regeneration in clients.

⏰ 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 – 425fc41f-5545-42a1-aeef-751fb6471b5a

No New Or Fixed Issues Found

[codecov]

Codecov Report

Attention: Patch coverage is 82.23684% with 27 lines in your changes missing coverage. Please review.

Project coverage is 63.58%. Comparing base (130ac6f) to head (cc34372).

Files with missing lines	Patch %	Lines
crates/bitwarden-wasm-internal/src/crypto.rs	0.00%	12 Missing ⚠️
crates/bitwarden-core/src/mobile/client_crypto.rs	0.00%	9 Missing ⚠️
crates/bitwarden-core/src/mobile/crypto.rs	95.41%	6 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main       #6      +/-   ##
==========================================
+ Coverage   63.34%   63.58%   +0.24%     
==========================================
  Files         184      184              
  Lines       12935    13087     +152     
==========================================
+ Hits         8194     8322     +128     
- Misses       4741     4765      +24     

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[dani-garcia]

Nice LGTM!