fix: import FileSystem expo-file-system/legacy (react-native)

[bhardwajparth51]

🐛 Problem & Fix

In Expo SDK 55 (expo-file-system@55.x), Expo moved legacy file system methods like readAsStringAsync and writeAsStringAsync to the expo-file-system/legacy subpath export.

Importing readAsStringAsync directly from top-level expo-file-system causes runtime crashes during chunked file uploads (> 5MB) on Expo SDK 55 applications.

This PR updates the template import in templates/react-native/src/services/template.ts.twig to import from expo-file-system/legacy, restoring compatibility for file uploads on Expo SDK 55.

Relates to appwrite/sdk-for-react-native#112

[greptile-apps]

Greptile Summary

Updates generated React Native services to use Expo’s legacy file-system export and adds the corresponding Rollup test alias.

• Imports FileSystem from expo-file-system/legacy for Expo SDK 55 compatibility.
• Maps the legacy subpath to the existing browser-compatible shim in React Native e2e builds.

Confidence Score: 5/5

The PR appears safe to merge.

The added exact-match Rollup alias addresses the previously reported shim bypass, and no blocking failure remains.

Important Files Changed

Filename	Overview
templates/react-native/src/services/template.ts.twig	Switches generated React Native services to Expo’s legacy file-system API subpath.
tests/e2e/languages/react-native/rollup.test.config.mjs	Adds the exact legacy-subpath alias needed to preserve the existing e2e file-system shim.

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