fix(iOS): cleanup the code, split into smaller functions

[okwasniewski]

Summary

This PR cleans up the code for iOS implementation.

• Move retrieval of event emitter to one shared function, (same as built-in React Native modal)
• Use #pragma mark for logic grouping of code
• Simplify conditions in scrollViewDidScroll

Test Plan

Test if everything works the same

What's required for testing (prerequisites)?

What are the steps to reproduce (after prerequisites)?

Compatibility

OS	Implemented
iOS	✅
Android	❌

Checklist

• I have tested this on a device and a simulator
• I added the documentation in README.md
• I updated the typed files (TS and Flow)

[Copilot]

Pull Request Overview

This PR refactors the iOS implementation of a React Native pager component to improve code organization and maintainability. The main focus is on cleaning up repetitive code patterns and improving logical grouping of methods.

• Extracted event emitter retrieval into a shared helper function
• Added #pragma mark directives to organize code into logical sections
• Simplified the scrollViewDidScroll method implementation