SIANXSVC-1204: Wrap response inside a result

The older pattern is not longer supported by e5e and therefore this
library needs to be fixed.

Closes SIANXSVC-1204

src/Anexia.E5E.Tests/Integration/E5ECommunicationServiceTests.cs

@@ -83,7 +83,7 @@ public async Task ShouldHaveCorrectStdoutFormatting()
 	{
 		await Host.StartWithTestEntrypointAsync(_ => E5EResponse.From("response"));
 		var (stdout, _) = await Host.WriteOnceAsync(builder => builder.WithData("request"));
-		Assert.Equal(@"+++{""data"":""response"",""type"":""text""}---", stdout);
+		Assert.Equal(@"+++{""result"":{""data"":""response"",""type"":""text""}}---", stdout);
 	}
 
 	[Fact]

src/Anexia.E5E.Tests/TestHelpers/TestHostBuilder.cs

@@ -119,10 +119,12 @@ private async Task<E5EResponse> ReadResponseAsync()
 		var json = stdout
 			.Replace(options.StdoutTerminationSequence, "")
 			.Replace(options.DaemonExecutionTerminationSequence, "");
-		var resp = JsonSerializer.Deserialize<E5EResponse>(json, E5EJsonSerializerOptions.Default);
 
-		// ReSharper disable once NullableWarningSuppressionIsUsed
-		return resp!;
+		var result = JsonSerializer.Deserialize<JsonElement>(json, E5EJsonSerializerOptions.Default);
+		if (!result.TryGetProperty("result", out result))
+			throw new InvalidOperationException("The response does not contain a 'result' property");
+
+		return result.Deserialize<E5EResponse>(E5EJsonSerializerOptions.Default)!;
 	}
 
 	public Task StartWithTestEntrypointAsync(Func<E5ERequest, E5EResponse> handler)

src/Anexia.E5E/Hosting/E5ECommunicationService.cs

@@ -1,3 +1,4 @@
+using System.Text;
 using System.Text.Json;
 
 using Anexia.E5E.Abstractions;
@@ -141,14 +142,19 @@ private async Task<string> ExecuteFunctionAsync(IE5EFunctionHandler handler, E5E
 		try
 		{
 			_logger.ReceivedResponse(response);
-			string json = "";
 #if NET8_0_OR_GREATER
-			json = JsonSerializer.Serialize(response, E5ESerializationContext.Default.E5EResponse);
+			var json = JsonSerializer.Serialize(response, E5ESerializationContext.Default.E5EResponse);
 #else
-			json = JsonSerializer.Serialize<E5EResponse>(response, E5EJsonSerializerOptions.Default);
+			var json = JsonSerializer.Serialize<E5EResponse>(response, E5EJsonSerializerOptions.Default);
 #endif
 
-			return _options.StdoutTerminationSequence + json;
+			// Although we could use a dedicated response class for serialization, this would create another overhead
+			// which is easily replaced with this string concatenation.
+			return new StringBuilder().Append(_options.StdoutTerminationSequence)
+				.Append("{\"result\":")
+				.Append(json)
+				.Append('}')
+				.ToString();
 		}
 		catch (Exception e)
 		{