[SM-1413] Resolve Concurrency Issues in C FFI

[coltonhurst]

🎟️ Tracking

https://bitwarden.atlassian.net/browse/SM-1413

📔 Objective

The Issue

Through the C FFI, we were running into concurrency issues with multiple Tokio runtimes.

A draft PR showing the concurrency issue with instructions can be found here.

The Fix

This PR fixes this issue for bitwarden-c and bitwarden-py, by preserving the runtime. Thanks @dani-garcia for the fix and working together on this one!

Extra

This also refactors the AccessTokenLogin type as a follow up for testing purposes for Go as initiated by this PR.

⏰ 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