Add OutputType property for executable configuration was missing the with xunit.v3 project

This commit adds the `<OutputType>` property set to `Exe` in the project file.
This change configures the project to produce an executable output, which may impact
the build and execution processes, especially in testing environments.
See dotnet/sdk#42722 (comment)

Author: christiannagel

src/clients/Codebreaker.GameAPIs.Client.Tests/Codebreaker.GameAPIs.Client.Tests.csproj

@@ -4,6 +4,7 @@
     <TargetFrameworks>net8.0;net9.0</TargetFrameworks>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
+		<OutputType>Exe</OutputType>
 
     <IsPackable>false</IsPackable>
     <IsTestProject>true</IsTestProject>