[PM-26064] Move Toast to BitwardenKit

[KatherineInCode]

🎟️ Tracking

https://bitwarden.atlassian.net/browse/PM-26064

📔 Objective

This moves our Toast functionality into BitwardenKit, as part of a broader effort to move our various components into BitwardenKit. This also updates this component in BWA.

📸 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
• 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 – 73aefb93-1952-4ac2-a182-68a5d9c3a59a

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

[codecov]

Codecov Report

❌ Patch coverage is 76.47059% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 75.74%. Comparing base (2cf0293) to head (f214589).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...UI/Vault/ItemList/ItemList/ItemListProcessor.swift	66.66%	2 Missing ⚠️
...I/Platform/Application/Utilities/Coordinator.swift	0.00%	1 Missing ⚠️
...gs/Settings/ImportItems/ImportItemsProcessor.swift	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2013      +/-   ##
==========================================
- Coverage   81.33%   75.74%   -5.60%     
==========================================
  Files         831     1015     +184     
  Lines       52451    61887    +9436     
==========================================
+ Hits        42663    46878    +4215     
- Misses       9788    15009    +5221     

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