[Dev Home][File Explorer][Version Control Selection Dropdown] Dropdown selector should include "Unassigned" as an option

tools/Customization/DevHome.Customization/ViewModels/FileExplorerViewModel.cs

@@ -306,4 +306,11 @@ private void AdjustFocus(object sender)
             _log.Information($"Set focus to add reposiotry card result: {isFocusSet}");
         }
     }
+
+    public void UnassignSourceControlProviderFromRepository(string repositoryRootPath)
+    {
+        ExtraFolderPropertiesWrapper.Unregister(repositoryRootPath);
+        RepoTracker.ModifySourceControlProviderForTrackedRepository(_unassigned, repositoryRootPath);
+        RefreshTrackedRepositories();
+    }
 }

tools/Customization/DevHome.Customization/Views/AddRepositoriesView.xaml.cs

@@ -43,6 +43,7 @@ private void SourceControlProviderMenuFlyout_Opening(object sender, object e)
     {
         if (sender is MenuFlyout menuFlyout)
         {
+            var stringResource = new StringResource("DevHome.Customization.pri", "DevHome.Customization/Resources");
             menuFlyout.Items.Clear();
 
             foreach (var extension in ViewModel.ExtensionService.GetInstalledExtensionsAsync(ProviderType.LocalRepository).Result)
@@ -54,10 +55,26 @@ private void SourceControlProviderMenuFlyout_Opening(object sender, object e)
                 };
                 menuItem.Click += AssignSourceControlProviderButton_Click;
 
-                var stringResource = new StringResource("DevHome.Customization.pri", "DevHome.Customization/Resources");
                 ToolTipService.SetToolTip(menuItem, stringResource.GetLocalized("PrefixForDevHomeVersion", extension.PackageDisplayName));
                 menuFlyout.Items.Add(menuItem);
             }
+
+            var unassignMenuItem = new MenuFlyoutItem
+            {
+                Text = stringResource.GetLocalized("MenuFlyoutUnregisteredRepository_Content"),
+            };
+            unassignMenuItem.Click += UnassignFolderButton_Click;
+            menuFlyout.Items.Add(unassignMenuItem);
+        }
+    }
+
+    public void UnassignFolderButton_Click(object sender, RoutedEventArgs e)
+    {
+        // Extract relevant data from view and give to view model for unassign
+        MenuFlyoutItem menuItem = (MenuFlyoutItem)sender;
+        if (menuItem.DataContext is RepositoryInformation repoInfo)
+        {
+            ViewModel.UnassignSourceControlProviderFromRepository(repoInfo.RepositoryRootPath);
         }
     }