Perform view updates during scroll tracking (#679)

When we enable floatingPanelScrollTracking on our view inside of the floating panel, some view updates are performed (i.e., SwiftUI views are being instantiated) but no rendering (i.e., body evaluations) occurs.

Example code:
```swift
content
    .floatingPanel(
        coordinator: ContentPanelCoordinator.self,
        onEvent: onEvent
    ) { proxy in
        panelContent
            .floatingPanelScrollTracking(proxy: proxy) // scroll tracking breaks view updates
    }
```

We tracked this down to the scroll tracking, and it seems that the performing of view updates inside of the ScrollViewRepresentable was missing.

This seems similar to #675.

Author: sgade

Sources/SwiftUI/View+floatingPanelScrollTracking.swift

@@ -68,7 +68,11 @@ private struct ScrollViewRepresentable<Content>: UIViewControllerRepresentable w
         return vc
     }
 
-    func updateUIViewController(_ uiViewController: ScrollViewHostingController<Content>, context: Context) {
+    func updateUIViewController(
+        _ uiViewController: ScrollViewHostingController<Content>,
+        context: Context
+    ) {
+        uiViewController.rootView = content()
     }
 
     class ScrollViewHostingController<V>: UIHostingController<V> where V: View {