Ignore strong naming warnings in tests and samples (#13700)

build/XUnit.props

@@ -13,5 +13,6 @@
   <PropertyGroup>
     <AssemblyOriginatorKeyFile>$(MSBuildThisFileDirectory)\avalonia.snk</AssemblyOriginatorKeyFile>
     <SignAssembly>False</SignAssembly>
+    <NoWarn>$(NoWarn);CS8002</NoWarn> <!-- ignore signing warnings for unit tests -->
   </PropertyGroup>
 </Project>

samples/Directory.Build.props

@@ -1,10 +1,14 @@
 <Project>
+
   <PropertyGroup>
-      <IsPackable>false</IsPackable>
-      <AvaloniaPreviewerNetCoreToolPath>$(MSBuildThisFileDirectory)..\src\tools\Avalonia.Designer.HostApp\bin\Debug\netcoreapp2.0\Avalonia.Designer.HostApp.dll</AvaloniaPreviewerNetCoreToolPath>
-      <EnableNETAnalyzers>false</EnableNETAnalyzers>
-      <LangVersion>11</LangVersion>
+    <IsPackable>false</IsPackable>
+    <AvaloniaPreviewerNetCoreToolPath>$(MSBuildThisFileDirectory)..\src\tools\Avalonia.Designer.HostApp\bin\Debug\netcoreapp2.0\Avalonia.Designer.HostApp.dll</AvaloniaPreviewerNetCoreToolPath>
+    <EnableNETAnalyzers>false</EnableNETAnalyzers>
+    <LangVersion>11</LangVersion>
+    <NoWarn>$(NoWarn);CS8002</NoWarn> <!-- ignore signing warnings for samples -->
   </PropertyGroup>
-  <Import Project="..\build\SharedVersion.props" />
-  <Import Project="..\build\DevAnalyzers.props" />
+
+  <Import Project="..\build\SharedVersion.props"/>
+  <Import Project="..\build\DevAnalyzers.props"/>
+
 </Project>