Implicit list row animations broken in Form container on iOS 26 beta 3

[Submitted as FB18870294, but posting here for visibility.]

In iOS 26 beta 3 (23A5287g), implicit animations no longer work when conditionally showing or hiding rows in a Form.

Rows with Text or other views inside a Section appear and disappear abruptly, even when wrapped in withAnimation or using .animation() modifiers. This is a regression from iOS 18.5, where the row item animates in and out correctly with the same code.

Repro Steps

1. Create a new iOS App › SwiftUI project.
2. Replace its ContentView struct with the code below
3. Build and run on an iOS 18 device.
4. Tap the Show Middle Row toggle and note how the Middle Row animates.
5. Build and run on an iOS 26 beta 3 device.
6. Tap the Show Middle Row toggle.

Expected

Middle Row item should smoothly animate in and out as it does on iOS 18.

Actual

Middle Row item appears and disappears abruptly, without any animation.

Code

struct ContentView: View {
    @State private var showingMiddleRow = false

    var body: some View {
        Form {
            Section {
                Toggle(
                    "Show **Middle Row**",
                    isOn: $showingMiddleRow.animation()
                )
                if showingMiddleRow {
                    Text("Middle Row")
                }
                Text("Last Row")
            }
        }
    }
}