Intl.NumberFormat can't always display the number's sign

### Description

`Intl.NumberFormat` has a [`signDisplay` option](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/NumberFormat/NumberFormat#signdisplay) that handles when to display the number sign. If we set it to `always` it should always display the sign, but React Native doesn't display a plus sign.

### Steps to reproduce

```js
// Tested with `en-US` as well without any difference.
const locale = 'sv-SE'

const numberFormatter = new Intl.NumberFormat(locale, { signDisplay: 'always' })
const percentFormatter = new Intl.NumberFormat(locale, { style: 'percent', signDisplay: 'always' })

numberFormatter.format(22) // Displays 22, but should display +22
percentFormatter.format(0.22) // Displays 22 %, but should display +22 %
```

### React Native Version

0.73.4

### Affected Platforms

Runtime - iOS

### Output of `npx react-native info`

```text
System:
OS: macOS 14.3
CPU: (10) arm64 Apple M2 Pro
Memory: 135.84 MB / 16.00 GB
Shell:
version: "5.9"
path: /bin/zsh
Binaries:
Node:
version: 18.18.2
path: ~/Library/Caches/fnm_multishells/59707_1707991116304/bin/node
Yarn:
version: 1.22.19
path: ~/code/seb/Spark-blackbird/apps/blackbird/node_modules/.bin/yarn
npm:
version: 9.8.1
path: ~/Library/Caches/fnm_multishells/59707_1707991116304/bin/npm
Watchman:
version: 2024.01.22.00
path: /opt/homebrew/bin/watchman
Managers:
CocoaPods:
version: 1.15.2
path: /Users/rickard/.rbenv/shims/pod
SDKs:
iOS SDK:
Platforms:
- DriverKit 23.2
- iOS 17.2
- macOS 14.2
- tvOS 17.2
- visionOS 1.0
- watchOS 10.2
Android SDK:
API Levels:
- "33"
- "34"
Build Tools:
- 30.0.3
- 33.0.0
- 33.0.1
- 34.0.0
System Images:
- android-33 | Google APIs ARM 64 v8a
- android-33 | Google Play ARM 64 v8a
- android-34 | Google APIs ARM 64 v8a
Android NDK: Not Found
IDEs:
Android Studio: 2023.1 AI-231.9392.1.2311.11255304
Xcode:
version: 15.2/15C500b
path: /usr/bin/xcodebuild
Languages:
Java:
version: 17.0.10
path: /usr/bin/javac
Ruby:
version: 3.2.2
path: /Users/rickard/.rbenv/shims/ruby
npmPackages:
"@react-native-community/cli":
installed: 13.5.1
wanted: "*"
react:
installed: 18.2.0
wanted: "*"
react-native:
installed: 0.73.4
wanted: "*"
react-native-macos: Not Found
npmGlobalPackages:
"*react-native*": Not Found
Android:
hermesEnabled: true
newArchEnabled: true
iOS:
hermesEnabled: true
newArchEnabled: false
```

### Stacktrace or Logs

```text
No stacktrace or logs
```

### Reproducer

https://snack.expo.dev/95Z5GGAwW7qZzA0Ne4Huf

### Screenshots and Videos

| Web | iOS |
| ------ | ----- |
|  |  |