[expo-manifests] Fix error in handling nested array (#23562)

# Why

Fix crash on iOS if a plugin is passed in as an array, but with only the
name element and not the props element.

Also fix co

[expo-manifests] Fix error in handling nested array (#23562)

# Why

Fix crash on iOS if a plugin is passed in as an array, but with only the
name element and not the props element.

Also fix corresponding code on Android, where an exception is thrown.

Fixes #23549.

# How

Modified `Manifest.swift` and `Manifest.kt` to handle the above case
correctly.

# Test Plan

- Tested with Expo Go and the project provided in the above issue
- New unit tests for both iOS and Android

# Checklist

- [x] Documentation is up to date to reflect these changes (eg:
https://docs.expo.dev and README.md).
- [x] Conforms with the [Documentation Writing Style
Guide](https://github.com/expo/expo/blob/main/guides/Expo%20Documentation%20Writing%20Style%20Guide.md)
- [x] This diff will work correctly for `npx expo prebuild` & EAS Build
(eg: updated a module plugin).

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