Address complete strict concurrency errors

Author: philium

Shared/Samples/Animate 3D graphic/Animate3DGraphicView.SettingsView.swift

@@ -38,6 +38,7 @@ extension Animate3DGraphicView {
         }
 
         /// The view content of the settings sheet.
+        @MainActor
         private var settingsContent: some View {
             NavigationStack {
                 content

Shared/Samples/Find route around barriers/FindRouteAroundBarriersView.Views.swift

@@ -88,6 +88,7 @@ extension FindRouteAroundBarriersView {
         }
 
         /// The content to display in the sheet with a title and done button.
+        @MainActor
         private var sheetContent: some View {
             NavigationStack {
                 content()

Shared/Samples/Group layers together/GroupLayersTogetherView.swift

@@ -67,6 +67,7 @@ struct GroupLayersTogetherView: View {
     }
 
     /// The list of group layers and their child layers that are currently added to the map.
+    @MainActor
     private var layersList: some View {
         NavigationStack {
             List {

Shared/Supporting Files/Models/Sample.swift

@@ -35,6 +35,7 @@ protocol Sample {
     var hasDependencies: Bool { get }
 
     /// Creates the view for the sample.
+    @MainActor
     func makeBody() -> AnyView
 }