feat(RN): Add wiring for protocol events - add ec.start

[kieran-osgood-shopify]

What changes are you making?

Part of the scope of this PR is to add a translation layer between the the core native SDKs and the React native JavaScript runtime.
The models that are generated for Swift and Kotlin automatically camel case at their encode decode boundary, which means the raw json is read as snake case and the Swift and Kotlin properties are then turned into camel case when they are turned back into raw json, they're back in snake_case.

This is problematic for React Native because we do not have a schema validation library. we are just using the CodeGen TypeScript interfaces, faces which again are in camelCase which means we need some layer to convert that over to camelCase.

I consider doing this on the TypeScript level

• This would require greater degrees of unsafe mapping due to the types at play
• I also didn't want to be blocking the main thread with lots of IO intensive work.

How to test

---

Before you merge

Important

• I've added tests to support my implementation
• I have read and agree with the Contribution Guidelines
• I have read and agree with the Code of Conduct
• I've updated the relevant platform README (platforms/swift/README.md and/or platforms/android/README.md)

---

Releasing a new Swift version?

• I have bumped the version in ShopifyCheckoutKit.podspec
• I have bumped the version in platforms/swift/Sources/ShopifyCheckoutKit/ShopifyCheckoutKit.swift
• I have updated platforms/swift/CHANGELOG.md
• I have updated the SwiftPM/CocoaPods version snippets in platforms/swift/README.md (major version only)

Releasing a new Android version?

• I have bumped the versionName in platforms/android/lib/build.gradle
• I have updated platforms/android/CHANGELOG.md
• I have updated the Gradle/Maven version snippets in platforms/android/README.md

Tip

See the Contributing documentation for the full release process per platform.

[kieran-osgood-shopify]

• feat(RN): Include remaining public protocol events from native #186
• feat(RN): Wire up accelerated checkouts with protocol events #181
• feat(RN): Add wiring for protocol events - add ec.start  #170 👈 (View in Graphite)
• feat(RN): replace addEventListener with callback args #119 : 2 other dependent PRs (#125 , #134 )
• feat(react-native): use local android/swift project references #115 : 1 other dependent PR (#116 )
• feat(protocol): add typescript interfaces #114
• main

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React Native — Coverage Report

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[kieran-osgood-shopify]

Need to improve the API here - seems like we might need a mapping layer, otherwise this unfortunately gives autocomplete of 'ec.start'