feat: add iOS shoppable ads interface for Rokt

[denischilik]

Background

This change introduces the Flutter API surface needed for shoppable ads while keeping behavior aligned with currently supported platforms.
The implementation is scoped to iOS support, with Android exposed as a compatibility no-op.

What Has Changed

• Added selectShoppableAds to the Flutter Rokt API and method channel flow
• Implemented iOS native bridge handling for roktSelectShoppableAds
• Added Android no-op handler for cross-platform API compatibility
• Updated iOS podspec to keep only the SDK umbrella dependency and rely on transitive pods
• Added test coverage for the new Flutter method call contract

Screenshots/Video

N/A

Checklist

• I have performed a self-review of my own code.
• I have made corresponding changes to the documentation.
• I have added tests that prove my fix is effective or that my feature works.
• I have tested this locally.

Additional Notes

selectShoppableAds is currently iOS-only. Android is intentionally a no-op and web is not implemented.

Made with Cursor

[cursor]

PR Summary

Medium Risk
Main risk is iOS build/integration fallout from removing explicit CocoaPods dependencies and relying on transitive resolution. Runtime behavior change is limited to a new optional API and an Android no-op handler.

Overview
Adds a new Flutter Rokt API selectShoppableAds, wiring a roktSelectShoppableAds method-channel call through to an iOS native implementation (including optional attributes/config and event subscription).

On Android the same method is now exposed but implemented as a no-op that logs a warning for cross-platform API compatibility, and the Dart test suite is extended to assert the new method-channel contract.

The iOS podspec is simplified to depend only on the mParticle-Apple-SDK umbrella pod (removing explicit ObjC and RoktContracts dependencies) and rely on transitive dependencies.

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