Ref System.Transactions only for .NET Fx

In the test project the assembly System.Transactions was referenced also for .NET (Core) which leads to a warning with the update to .NET 8. Now we reference it only for the .NET Framework targets.

Author: ckadluba

test/Serilog.Sinks.MSSqlServer.Tests/Serilog.Sinks.MSSqlServer.Tests.csproj

@@ -38,6 +38,7 @@
 
   <ItemGroup Condition=" '$(TargetFramework)' == 'net472' Or '$(TargetFramework)' == 'net462' ">
     <Reference Include="Microsoft.CSharp" />
+    <Reference Include="System.Transactions" />
     <Compile Include="Configuration\Extensions\Hybrid\**\*.cs" />
     <Compile Include="Configuration\Implementations\Microsoft.Extensions.Configuration\**\*.cs" />
     <Compile Include="Configuration\Implementations\System.Configuration\**\*.cs" />
@@ -53,10 +54,6 @@
     <Compile Include="Configuration\Implementations\System.Configuration\**\*.cs" />
   </ItemGroup>
 
-  <ItemGroup>
-    <Reference Include="System.Transactions" />
-  </ItemGroup>
-
   <ItemGroup>
     <None Update="App.config">
       <CopyToOutputDirectory>Always</CopyToOutputDirectory>