stop back button minimizing signal-windows when we handled the event

Author: Trolldemorted

Signal-Windows/ViewModels/AddContactPageViewModel.cs

@@ -56,6 +56,7 @@ internal void BackButton_Click(object sender, BackRequestedEventArgs e)
             if (UIEnabled)
             {
                 View.Frame.GoBack();
+                e.Handled = true;
             }
         }
 

Signal-Windows/ViewModels/LinkPageViewModel.cs

@@ -156,6 +156,7 @@ await Task.Run(() =>
                     LibsignalDBContext.PurgeAccountData();
                 });
                 View.Frame.GoBack();
+                e.Handled = true;
             }
         }
     }

Signal-Windows/ViewModels/MainPageViewModel.cs

@@ -79,6 +79,7 @@ internal async void BackButton_Click(object sender, BackRequestedEventArgs e)
                 WelcomeVisibility = Visibility.Visible;
                 View.SwitchToStyle(View.GetCurrentViewStyle());
                 Utils.DisableBackButton(BackButton_Click);
+                e.Handled = true;
             }
         }
 

Signal-Windows/ViewModels/RegisterFinalizationPageViewModel.cs

@@ -141,6 +141,7 @@ private void BackButton_Click(object sender, BackRequestedEventArgs e)
             if(UIEnabled)
             {
                 View.Frame.GoBack();
+                e.Handled = true;
             }
         }
 

Signal-Windows/ViewModels/RegisterPageViewModel.cs

@@ -100,6 +100,7 @@ public void OnNavigatedTo()
         private void BackButton_Click(object sender, BackRequestedEventArgs e)
         {
             View.Frame.GoBack();
+            e.Handled = true;
         }
 
         public void ComboBox_SelectionChanged(object sender, SelectionChangedEventArgs e)