JsonSchemaExporter doesn't respect IgnoreReadOnlyProperties/IgnoreReadOnlyFields

[Youssef1313]

Description

The IgnoreReadOnlyProperties and IgnoreReadOnlyFields options are not taken into consideration by the JsonSchemaExporter today.

A property that is never serialized or deserialized is still emitting as part of the JSON schema.

Reproduction Steps

using System;
using System.Text.Json;
using System.Text.Json.Schema;

var options = new JsonSerializerOptions(JsonSerializerOptions.Default)
{
    IgnoreReadOnlyProperties = true,
    IgnoreReadOnlyFields = true,
};

Console.WriteLine("Serialized object:");
Console.WriteLine(JsonSerializer.Serialize(new C(), options));

Console.WriteLine();
Console.WriteLine("======");
Console.WriteLine();

Console.WriteLine("Json schema:");
Console.WriteLine(options.GetJsonSchemaAsNode(typeof(C)));


class C
{
    public string S => "Hello";
}

Expected behavior

Output is:

Serialized object:
{}

======

Json schema:
{
  "type": [
    "object",
    "null"
  ]
}

Actual behavior

Output is:

Serialized object:
{}

======

Json schema:
{
  "type": [
    "object",
    "null"
  ],
  "properties": {
    "S": {
      "type": [
        "string",
        "null"
      ]
    }
  }
}

Regression?

No response

Known Workarounds

No response

Configuration

No response

Other information

No response

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