Remove FXIOS-15234 [Feature flag clean up] Remove felt deletion

[lmarceau]

📜 Tickets

Jira ticket
Github issue

💡 Description

This feature has not been enabled after experimentation and the work is stale. Both the flag and the feature are now removed.

📝 Checklist

• I filled in the ticket numbers and a description of my work
• I updated the PR name to follow our PR naming guidelines
• I ensured unit tests pass and wrote tests for new code
• If working on UI, I checked and implemented accessibility (Dynamic Text and VoiceOver)
• If adding telemetry, I read the data stewardship requirements and will request a data review
• If adding or modifying strings, I read the guidelines and will request a string review from l10n
• If needed, I updated documentation and added comments to complex code

[mobiletest-ci-bot]

	Warnings
⚠️	Detected telemetry changes in: firefox-ios/Client/Glean/probes/metrics.yaml, firefox-ios/Client/Glean/probes/toolbar.yaml (cc @ih-codes @adudenamedruby)

	Messages
📖	Project coverage: 41.08%

✍️ Strings Updated

Detected changes in Shared/Strings.swift.
To keep strings up to standards, please add a member of the firefox-ios-l10n team as reviewer. 🌍

💪 Quality guardian

8 tests files modified. You're a champion of test coverage! 🚀

🧩 Neat Piece

This PR changes 684 lines. It's a substantial update,
but still review-friendly if there’s a clear description. Thanks for keeping things moving! 🚀

🎉 BrowserViewController got smaller

Nice! BrowserViewController.swift got smaller by 17 lines.

✅ New file code coverage

No new file detected so code coverage gate wasn't ran.

Client.app: Coverage: 39.43

File	Coverage
GeneralBrowserAction.swift	100.0%	✅
BrowserViewController.swift	34.48%	⚠️
FeatureFlagsDebugViewController.swift	0.0%	⚠️
ContextualHintViewProvider.swift	19.0%	⚠️
ContextualHintCopyProvider.swift	0.0%	⚠️
ToolbarActionConfiguration.swift	95.65%	✅
BrowserViewController+ToolBarActionMenuDelegate.swift	6.11%	⚠️
BrowserViewControllerState.swift	50.5%	✅
AddressBarState.swift	93.37%	✅
NavigationBarState.swift	86.1%	✅
ContextualHintEligibilityUtility.swift	76.67%	✅
ToolbarState.swift	87.03%	✅
ToolbarAction.swift	100.0%	✅
ContextualHintPrefsKeysProvider.swift	100.0%	✅
NimbusFlaggableFeature.swift	95.77%	✅
NimbusFeatureFlagLayer.swift	82.03%	✅
ToolbarTelemetry.swift	100.0%	✅
ToolbarMiddleware.swift	94.16%	✅

Shared: Coverage: 61.1

File	Coverage
Prefs.swift	83.7%	✅

Generated by 🚫 Danger Swift against e77228b