skip flaky SecureDataFormatTest in Helix (#8129)

related #7366

src/Security/Authentication/test/Microsoft.AspNetCore.Authentication.Test.csproj

@@ -29,6 +29,10 @@
     <EmbeddedResource Include="OpenIdConnect\wellknownkeys.json" />
   </ItemGroup>
 
+  <ItemGroup>
+    <Compile Include="$(SharedSourceRoot)test\SkipOnHelixAttribute.cs" />
+  </ItemGroup>
+
   <ItemGroup>
     <Reference Include="Microsoft.AspNetCore.Authentication.Cookies" />
     <Reference Include="Microsoft.AspNetCore.Authentication.Facebook" />

src/Security/Authentication/test/SecureDataFormatTests.cs

@@ -4,6 +4,7 @@
 using System;
 using System.Text;
 using Microsoft.AspNetCore.DataProtection;
+using Microsoft.AspNetCore.Testing.xunit;
 using Microsoft.Extensions.DependencyInjection;
 using Xunit;
 
@@ -48,6 +49,7 @@ namespace Microsoft.AspNetCore.Authentication.DataHandler
         }
 
         [Fact]
+        [SkipOnHelix]
         public void UnprotectWithDifferentPurposeFails()
         {
             var provider = ServiceProvider.GetRequiredService<IDataProtectionProvider>();