[FSSDK-11454] Swift - Add SDK Multi-Region Support for Data Hosting

[esrakartalOpt]

Summary

• Add Multi-Region Support for Data Hosting

Test plan

• Created and added new test cases

Issues

• FSSDK-11454

[Copilot]

Pull Request Overview

This PR adds multi-region support for data hosting in the Optimizely Swift SDK, allowing events to be sent to different regional endpoints based on configuration.

• Add Region enum with US and EU support to Project and ProjectConfig models
• Update event building and dispatching to include region information and use appropriate endpoints
• Modify user context creation to accept an optional region parameter

Reviewed Changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
BatchEventBuilderTests_Region.swift	Comprehensive test suite covering region functionality for impression/conversion events
OptimizelyUserContext.swift	Add optional region parameter to user context initialization
OptimizelyUserContext+ObjC.swift	Update Objective-C wrapper to support region parameter with US default
BatchEventBuilder.swift	Include region information in event creation and encoding
ArrayEventForDispatch+Extension.swift	Add region validation to event batching logic
ProjectConfig.swift	Add computed property to get region with US default
Project.swift	Add Region enum and region field to Project model
EventForDispatch.swift	Add region-based endpoint selection and region parameter to initializer
BatchEvent.swift	Add region field to batch event structure

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[pvcraven]

Adds region support. Might want to add a test case for what happens if a country other than "US" and "EU" is specified.