title: Two UINavigationControllers after using NavigationLink in sheet
body: <p>I have a modal sheet that is presented from my home view as such:</p>
  
  <pre><code>    Button(action: {
          ...
      }) {
          ...
      }
      .sheet(isPresented: ...) {
          MySheetView()
      }
  </code></pre>
  
  <p>In <code>MySheetView</code>, there is a <code>NavigationView</code> and a <code>NavigationLink</code> to push another view onto its view stack (while I'm on <code>MySheetView</code> screen and use the view inspector, there's only one <code>UINavigationController</code> associated with it which is what I expect).</p>
  
  <p>However, as soon as I get to my next view that is presented from <code>MySheetView</code> using the <code>NavigationLink</code>, and I use the view hierarchy debugger, there are <strong>TWO</strong> <code>UINavigationControllers</code> on-top of each other. Note, this view does NOT have a <code>NavigationView</code> inside it, only <code>MySheetView</code> does.</p>
  
  <p>Does anyone know what's going on here? I have a feeling this is causing some navigation bugs im experiencing. This can be easily reproduced in an example app with the same structure.</p>
  
  <p>Ex:</p>
  
  <pre><code>// These are 3 separate SwiftUI files
  struct ContentView: View {
  
      @State var isPresented = false
  
      var body: some View {
          NavigationView {
              Button(action: { self.isPresented = true }) {
                  Text("Press me")
              }
              .sheet(isPresented: $isPresented) { 
                  ModalView()
              }
          }
      }
  }
  
  struct ModalView: View {
      var body: some View {
          NavigationView {
              NavigationLink(destination: FinalView()) {
                  Text("Go to final")
              }
          }
      }
  }
  
  struct FinalView: View {
      var body: some View {
          Text("Hello, World!")
      }
  }
  </code></pre>