Fix warnings

SpeedrunTracker/App.xaml.cs

@@ -1,4 +1,5 @@
-namespace SpeedrunTracker;
+
+namespace SpeedrunTracker;
 
 public partial class App : Application
 {
@@ -8,6 +9,10 @@ public App(ILocalSettingsService settingsService)
     {
         InitializeComponent();
         UserAppTheme = settingsService.UserSettings.Theme;
-        MainPage = new AppShell();
+    }
+
+    protected override Window CreateWindow(IActivationState activationState)
+    {
+        return new Window(new AppShell());
     }
 }

SpeedrunTracker/Services/DialogService.cs

@@ -1,14 +1,18 @@
-namespace SpeedrunTracker.Services;
+using Microsoft.Maui.Controls.PlatformConfiguration;
+
+namespace SpeedrunTracker.Services;
 
 public class DialogService : IDialogService
 {
     public Task ShowAlertAsync(string title, string message, string cancel = "OK")
     {
-        return Application.Current.MainPage.DisplayAlert(title, message, cancel);
+        return GetMainPage()?.DisplayAlert(title, message, cancel);
     }
 
     public Task<bool> ShowConfirmationAsync(string title, string message, string accept = "Yes", string cancel = "No")
     {
-        return Application.Current.MainPage.DisplayAlert(title, message, accept, cancel);
+        return GetMainPage()?.DisplayAlert(title, message, accept, cancel);
     }
+
+    private Page GetMainPage() => Application.Current.Windows[0].Page;
 }