[iOS] Settings:fileName property causes Settings to fail

Background

macOS 10.15.4

iOS 14.6

Observed behavior

When setting the `fileName` property and deploying to macOS, the appropriately-named file appears in the app bundle, in `Contents/MacOS`. On subsequent runs, the app fetches and loads the data correctly.

However, when the identical code is compile and deployed to iOS, the app fails to fetch and load the saved data. I am unfamiliar with the iOS file system and thus cannot confirm if the file is being  appropriately generated.

P.S. Note, that using the `category` property works for both macOS and iOS.

Expected behavior

The app should behave identically no matter if it is compiled for iOS or macOS.