Change warning suppression from WarningsNotAsErrors to NoWarn for IL2026 in Uno project properties

Author: Arlodotexe

ProjectHeads/App.Head.Uno.props

@@ -9,7 +9,7 @@
 
   <PropertyGroup Condition="'$(IsUno)' == 'true'">
     <!-- Code generated by Uno.UI.SourceGenerators creates AoT-unsafe code when Behaviors are used.  -->
-    <WarningsNotAsErrors>$(WarningsNotAsErrors);IL2026</WarningsNotAsErrors>
+    <NoWarn>$(NoWarn);IL2026</NoWarn>
 
     <!--
       Suppression of error Uno0006: