added expo support to NSHealthClinicalHealthRecordsShareUsageDescription

[epalacio90]

Description

The expo plugin doesn't have support for NSHealthClinicalHealthRecordsShareUsageDescription, so I added the support to also modify that from app.config.js

I've also tested that the Info.plist has been modified correctly after running expo prebuild

Fixes # (issue)

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• I have checked my code and corrected any misspellings