UWP .NET9 (#555)

* Ground work for NET9 UWP switch.

* Add launch settings for Wino.Mail

* Added new test WAP project

* fix platforms in slnx solution

* ManagePackageVersionsCentrally set default

* Fixing assets and couple issues with the new packaging project.

* Add back markdown

* Fix nuget warnings

* FIx error in WAP about build tools

* Add build.props with default language preview

* Some AOT compilation progress.

* More AOT stuff.

* Remove deprecated protocol auth activation handler.

* Fix remaining protocol handler for google auth.

* Even more AOT

* More more AOT fixes

* Fix a few more AOT warnings

* Fix signature editor AOT

* Fix composer and renderer AOT JSON

* Outlook Sync AOT

* Fixing bundle generation and package signing.

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Co-authored-by: Burak Kaan Köse <bkaankose@outlook.com>

Wino.Mail/MenuFlyouts/AccountSelectorFlyout.cs

@@ -10,7 +10,7 @@ using Wino.Helpers;
 
 namespace Wino.MenuFlyouts
 {
-    public class AccountSelectorFlyout : MenuFlyout, IDisposable
+    public partial class AccountSelectorFlyout : MenuFlyout, IDisposable
     {
         private readonly IEnumerable<MailAccount> _accounts;
         private readonly Func<MailAccount, Task> _onItemSelection;