title: SwiftUI preview issue while using environment locale
body: <p>I am using a simple view to display text in <code>NumberFormatter</code> for a specific locale</p>
  
  <pre><code>struct CurrencyView: View {
      let currency:Currency
      var body: some View {
          Text(currency.getFormattedCurrency())
      }
  }
  
  struct CurrencyView_Previews: PreviewProvider {
      static var previews: some View {
          CurrencyView(currency: Currency(currencyValue: 1.0)).previewLayout(.fixed(width: 300.0, height: 55.0)).environment(\.locale, .init(identifier: "fr_Fr"))
      }
  }
  
  struct Currency{
      let currencyValue:Double
  
      func getFormattedCurrency() -&gt; String{
          let formatter = NumberFormatter()
          formatter.numberStyle = .currency
          let formatterCurrency =  formatter.string(for: self.currencyValue) ?? ""
          return formatterCurrency
      }
  }
  </code></pre>
  
  <p>I was expecting the preview will show currency in <code>French</code> with € as I have already mentioned in Locale in preview.</p>