Preserve Expo-generated modulemap in replace-rncore-version.js

[Insik-Han]

Summary

When using Expo with use_frameworks! in the Podfile, Expo generates a React-use-frameworks.modulemap file inside React-Core-prebuilt. When replaceRNCoreConfiguration runs (e.g., when switching between Debug and Release builds), this file can be lost, causing subsequent builds to fail with modulemap-related errors.

The current code removes only directories inside React-Core-prebuilt (preserving top-level files), but React-use-frameworks.modulemap may reside inside one of those subdirectories depending on the Expo version. This PR explicitly saves and restores the modulemap around the directory replacement to make the intent clear and guard against this case.

The restore is placed inside the finally block so it runs even if mv/cp partially fails during the directory move.

Changelog:

[IOS] [Fixed] - Preserve Expo-generated React-use-frameworks.modulemap across replace-rncore-version.js runs

Test Plan

• Set up an Expo project with use_frameworks! in Podfile
• Run pod install for a Debug build
• Switch to a Release build to trigger replace-rncore-version.js
• Verify React-use-frameworks.modulemap is present in React-Core-prebuilt/ after the replacement
• Confirm the build succeeds without modulemap-related errors

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