feat: allow customization of Local Network message for Expo projects on iOS

[ts-candide]

Summary

Allow customisation of the pop-up message that appears when an Expo-based app attempts to connect to an Internet card reader for the first time, on iOS.

Motivation

On iOS 14+, the first time that the app attempts to connect to an Internet card reader (such as the WisePOS), a message appears asking the user to allow access to the Local Network. The description that appears can be customised by setting the NSLocalNetworkUsageDescription property list key. This change allows the description to be customised in an Expo app by setting the localNetworkUsagePermission property in the relevant plugin config.

Testing

• I tested this manually
• I added automated tests

Documentation

Select one:

• I have added relevant documentation for my changes.
• This PR does not result in any developer-facing changes.

If/when this is merged and released, this will require changes to the setup integration docs.

[CLAassistant]

All committers have signed the CLA.