Scope setting warning level to when AOT is enabled.

Author: manodasanW

src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Windows.targets

@@ -50,7 +50,7 @@ Copyright (c) .NET Foundation. All rights reserved.
     <CsWinRTAotOptimizerEnabled Condition="'$(CsWinRTAotOptimizerEnabled)' == '' and $([MSBuild]::GetTargetFrameworkVersion('$(TargetFramework)')) >= 6">true</CsWinRTAotOptimizerEnabled>
     <CsWinRTAotExportsEnabled Condition="'$(CsWinRTAotExportsEnabled)' == '' and '$(CsWinRTAotOptimizerEnabled)' == 'true' and '$(PublishAot)' == 'true'">true</CsWinRTAotExportsEnabled>
     <CsWinRTCcwLookupTableGeneratorEnabled Condition="'$(CsWinRTCcwLookupTableGeneratorEnabled)' == '' and '$(CsWinRTGenerateProjection)' != 'true'">true</CsWinRTCcwLookupTableGeneratorEnabled>
-    <CsWinRTAotWarningLevel Condition="'$(CsWinRTAotWarningLevel)' == '' and '$(CsWinRTGenerateProjection)' != 'true'">1</CsWinRTAotWarningLevel>
+    <CsWinRTAotWarningLevel Condition="'$(CsWinRTAotWarningLevel)' == '' and '$(CsWinRTGenerateProjection)' != 'true' and ('$(PublishAot)' == 'true' or '$(IsAotCompatible)' == 'true')">1</CsWinRTAotWarningLevel>
   </PropertyGroup>
 
   <ItemGroup Condition="'$(IncludeWindowsSDKRefFrameworkReferences)' == 'true'">