Update GamesClientTests and version to 3.9.0

Modified the GamesClientTests constructor to include an optional
ITestOutputHelper parameter. Removed the gameId variable and added
a JSON string for a game object. Updated the version in
Codebreaker.GameAPIs.Client.csproj from 3.8.0 to 3.9.0.

Author: christiannagel

src/clients/Codebreaker.GameAPIs.Client.Tests/GamesClientTests.cs

@@ -678,7 +678,6 @@ private static (HttpClient Client, Mock<HttpMessageHandler> Handler) GetHttpClie
         Mock<IConfiguration> configMock = new();
         configMock.Setup(x => x[It.IsAny<string>()]).Returns("http://localhost:5000");
         Mock<HttpMessageHandler> handlerMock = new(MockBehavior.Strict);
-        var gameId = "91f3c729-5e6e-459a-b656-2d77f3f45dd9";
         string getReturnMessage = """
         {
           "id": "91f3c729-5e6e-459a-b656-2d77f3f45dd9",

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

@@ -15,7 +15,7 @@
     </Description>
     <PackageReadmeFile>readme.md</PackageReadmeFile>
     <PackageIcon>codebreaker.jpeg</PackageIcon>
-	  <Version>3.8.0</Version>
+	  <Version>3.9.0</Version>
 		<ManagePackageVersionsCentrally>false</ManagePackageVersionsCentrally>
   </PropertyGroup>