Fix SYSLIB0051

Warning was introduced in net8.0

Author: ATimmeh33

src/SignhostAPIClient/SignhostAPIClient.csproj

@@ -6,7 +6,6 @@
 		<DefineConstants Condition="'$(TargetFramework)' == 'netstandard2.0'">TYPEINFO</DefineConstants>
 		<DefineConstants Condition="'$(TargetFramework)' == 'netstandard2.0'">SERIALIZABLE</DefineConstants>
 		<DefineConstants Condition="'$(TargetFramework)' == 'net8.0'">TYPEINFO</DefineConstants>
-		<DefineConstants Condition="'$(TargetFramework)' == 'net8.0'">SERIALIZABLE</DefineConstants>
 		<RootNamespace>Signhost.APIClient</RootNamespace>
 	</PropertyGroup>