BugFix Issue #3731 json schema input schema

[RogerBarreto]

This pull request introduces changes to improve the handling of Document objects and schema generation in the BedrockChatClient class within the AWSSDK.Extensions.Bedrock.MEAI extension. The updates streamline the creation of input schemas and ensure consistency in Document initialization.

• Fix The json schema definition at toolConfig.tools.10.toolSpec.inputSchema is invalid #3731

Fix to Document default:

This change prevents an error while advertising the function result back to the API, as it says the toolInput cannot be null, by setting the default as empty dictionary sorts the error.

Enhancements to schema generation:

• handling type, properties, and required fields in a more structured manner, this avoid advertising those properties when they are not present. Any execution of a function that has no arguments were failing before this fix.

Reproduction Bug

using Amazon.BedrockRuntime;
using Microsoft.Extensions.AI;
using Microsoft.Extensions.DependencyInjection;
using System.Globalization;

var services = new ServiceCollection();
services.TryAddAWSService<IAmazonBedrockRuntime>();

var runtime = services.BuildServiceProvider().GetRequiredService<IAmazonBedrockRuntime>();

var chatClient = runtime.AsIChatClient().AsBuilder().UseFunctionInvocation().Build();

var aiFunction = AIFunctionFactory.Create(() => DateTime.UtcNow.ToString("d", CultureInfo.InvariantCulture), "GetCurrentDate", "Returns the current date in UTC format.");

var chatOptions = new ChatOptions
{
    ModelId = "anthropic.claude-3-5-sonnet-20240620-v1:0",
    Tools = [aiFunction],
};

var response = await chatClient.GetResponseAsync([
    new ChatMessage(ChatRole.User, "What is the current date?"),
], chatOptions);

Console.WriteLine($"Response: {response}");

[RogerBarreto]

I miss a place to add integration tests in this repo, if we can hook up any with the support of the team would be very helpful to ensure the functionality. Currently I had to create a test on my local side and only this way was capable of replicating the problem and solving it.