revert: downgrade WindowsAppSDK to 1.8.x per maintainer request

Per @Belim's feedback on PR #21: SDK 2.0 upgrade is too big a jump at
this stage. Revert WindowsAppSDK to 1.8.260209005 and BuildTools to
10.0.26100.4654 to match upstream.

Author: Stensel8

FluentCleaner/FluentCleaner.csproj

@@ -21,8 +21,8 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.WindowsAppSDK" Version="2.0.1" />
-    <PackageReference Include="Microsoft.Windows.SDK.BuildTools" Version="10.0.28000.1839" PrivateAssets="all" />
+    <PackageReference Include="Microsoft.WindowsAppSDK" Version="1.8.260209005" />
+    <PackageReference Include="Microsoft.Windows.SDK.BuildTools" Version="10.0.26100.4654" PrivateAssets="all" />
     <PackageReference Include="CommunityToolkit.Mvvm" Version="8.4.2" />
   </ItemGroup>