feat(ios): ai button feature flag (#13280)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **New Features**
  * Added a global API to check the AI button feature flag status.

* **Bug Fixes**
* Improved handling for the AI button feature: the app now checks the
feature flag before proceeding and provides a clear error if the feature
is disabled.

* **Refactor**
  * Removed all AI button presentation and dismissal logic from the app.
* Deleted unused plugin interfaces and registration related to the AI
button feature.

* **Chores**
  * Updated project metadata and build configuration for iOS.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/frontend/apps/ios/App/App.xcodeproj/project.pbxproj

@@ -3,7 +3,7 @@
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@@ -339,9 +337,13 @@
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