NavigationStack and toolbar incompatibility

I have the following view setup. A content view with TextField in the toolbar position .principal (so, inside the NavigationBar in iOS) and a button that toggles focus on the TextField. As well as an enclosing view handling some navigation.

struct FocusStateView: View {
    @FocusState private var isFocused: Bool
    @State private var username = "Anonymous"

    var body: some View {
            VStack {
                Button("Toggle Focus") {
                    isFocused.toggle()
                }
            }
            .toolbar {
                ToolbarItem(placement: .principal) {
                    TextField("Enter your username", text: $username)
                        .focused($isFocused)
                }
            }
    }
}

struct NavigationWrapper: View {
    @State private var path = NavigationPath()

    var body: some View {
        NavigationStack(path: $path) {
            FocusStateView()
                .navigationDestination(for: Int.self) { _ in
                    ContentView()
                }
        }
    }
}

This setup doesn't work unless either the .navigationDestination modifier is moved inside of FocusStateView or the TextField is moved from the toolbar into the VStack.

So the following would be working:

```swift
struct FocusStateView: View {
    @FocusState private var isFocused: Bool
    @State private var username = "Anonymous"

    var body: some View {
            VStack {
                Button("Toggle Focus") {
                    isFocused.toggle()
                }
            }
            .toolbar {
                ToolbarItem(placement: .principal) {
                    TextField("Enter your username", text: $username)
                        .focused($isFocused)
                }
            }
            .navigationDestination(for: Int.self) { _ in
                ContentView()
            }
    }
}

struct NavigationWrapper: View {
    @State private var path = NavigationPath()

    var body: some View {
        NavigationStack(path: $path) {
            FocusStateView()
        }
    }
}

This looks like a bug to me, but please let me know if I'm handling something in the wrong way.

Essentially I would like to keep all the navigation related logic in NavigationWrapper if possible.