[PM-9267] Implement feature flag for inline menu re-architecture

[cagonzalezcs]

🎟️ Tracking

https://bitwarden.atlassian.net/browse/PM-9267

📔 Objective

This PR is being made with consideration to the scope of behavioral changes within https://github.com/bitwarden/clients/pull/8431

We want to ensure that the inline menu positioning enhancement can be reversed in the case of unexpected issues when deployed.

This work for this ticket sets up a feature flag to enable the re-architected overlay, pulling the deprecated implementation into a separate folder that will be removed once we are confident in the updated inline menu implementation.

⏰ 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 89.74359% with 128 lines in your changes missing coverage. Please review.

Project coverage is 30.91%. Comparing base (e560711) to head (33e1226).

Files	Patch %	Lines
...ces/autofill-overlay-content.service.deprecated.ts	90.85%	20 Missing and 13 partials :warning:
...ecated/background/overlay.background.deprecated.ts	90.58%	7 Missing and 17 partials :warning:
...tent/autofill-overlay-iframe.service.deprecated.ts	91.27%	4 Missing and 9 partials :warning:
...lay/pages/list/autofill-overlay-list.deprecated.ts	94.65%	0 Missing and 13 partials :warning:
apps/browser/src/background/main.background.ts	0.00%	11 Missing :warning:
...cated/content/bootstrap-legacy-autofill-overlay.ts	0.00%	9 Missing :warning:
...ill/deprecated/content/autofill-init.deprecated.ts	92.55%	0 Missing and 7 partials :warning:
...shared/autofill-overlay-page-element.deprecated.ts	87.23%	4 Missing and 2 partials :warning:
...on/bootstrap-autofill-overlay-button.deprecated.ts	0.00%	5 Missing :warning:
...list/bootstrap-autofill-overlay-list.deprecated.ts	0.00%	5 Missing :warning:
... and 2 more

Additional details and impacted files

```diff @@ Coverage Diff @@ ## autofill/pm-5189-fix-issues-present-with-inline-menu-rendering-in-iframes #9845 +/- ## ============================================================================================================= + Coverage 29.94% 30.91% +0.97% ============================================================================================================= Files 2540 2553 +13 Lines 74601 75842 +1241 Branches 13942 14208 +266 ============================================================================================================= + Hits 22338 23450 +1112 - Misses 50589 50656 +67 - Partials 1674 1736 +62 ```

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[github-actions[bot]]

Checkmarx One – Scan Summary & Details – 6629b44b-9be8-4b4b-a6cc-8c594f225900

New Issues

Severity	Issue	Source File / Package	Checkmarx Insight
	Client_Use_Of_Iframe_Without_Sandbox	/apps/browser/src/autofill/deprecated/overlay/iframe-content/autofill-overlay-iframe.service.deprecated.ts: 90	Attack Vector