Add 'net9.0-windows10.0.26100.0' TFM to UWP

Author: Sergio0694

MultiTarget/AvailableTargetFrameworks.props

@@ -2,7 +2,9 @@
     <PropertyGroup>
         <!-- See https://github.com/CommunityToolkit/Tooling-Windows-Submodule/pull/235#issuecomment-2530131559 -->
         <UwpTargetFramework Condition="'$(UwpTargetFramework)' == '' AND '$(BuildingInsideVisualStudio)' == 'true'">uap10.0.17763;</UwpTargetFramework>
-        <UwpTargetFramework Condition="'$(UwpTargetFramework)' == '' AND '$(BuildingInsideVisualStudio)' != 'true'">uap10.0.17763;net8.0-windows10.0.26100.0;</UwpTargetFramework>
+
+        <!-- We also include 'net9.0-windows10.0.26100.0' explicitly as a workaround for https://github.com/CommunityToolkit/Tooling-Windows-Submodule/issues/238 -->
+        <UwpTargetFramework Condition="'$(UwpTargetFramework)' == '' AND '$(BuildingInsideVisualStudio)' != 'true'">uap10.0.17763;net8.0-windows10.0.26100.0;net9.0-windows10.0.26100.0;</UwpTargetFramework>
         <WinAppSdkTargetFramework Condition="'$(WinAppSdkTargetFramework)' == ''">net9.0-windows10.0.19041.0;net8.0-windows10.0.19041.0;</WinAppSdkTargetFramework>
 
         <WasmHeadTargetFramework Condition="'$(WasmHeadTargetFramework)' == ''">net9.0;</WasmHeadTargetFramework>