`class additional_properties_validator` does not honour `walk_result::advance`

[NiN9876]

Describe the bug

There is a bug in class additional_properties_validator which terminates the loop over the instances after the first item even when the reporter function returns walk_result::advance

jsoncons/include/jsoncons_ext/jsonschema/common/keyword_validator.hpp

Line 2939 in 0dac681

break;

Enumerate the steps to reproduce the bug
This test fails since the size of the result size is 1, not 2

    TEST(JsonconsTests, SchemaReporter_MultipleAdditionalValues)
    {
        std::vector<jsoncons::jsonschema::validation_message> result;

        auto reporter =
            [&result](const jsoncons::jsonschema::validation_message& message) -> jsoncons::jsonschema::walk_result
        {
            std::cout << "+++++++++++++++++" << std::endl;
            std::cout << "message: " << message.message() << std::endl;
            std::cout << "instance location: " << message.instance_location().string() << std::endl;
            std::cout << "schema location: " << message.schema_location().string() << std::endl;
            std::cout << "keyword: " << message.keyword() << std::endl;
            std::cout << "evaluation path: " << message.eval_path().string() << std::endl;
            std::cout << "+++++++++++++++++" << std::endl;
            std::cout << std::endl;

            result.push_back(message);
            return jsoncons::jsonschema::walk_result::advance;
        };

        std::string schemaString = R"(
    {
        "$schema" : "https://json-schema.org/draft/2020-12/schema",
        "type" : "object",
        "additionalProperties" : false,
        "required" : [ "s1" ],
        "properties" : {
            "s1" : {"type" : "string"},
            "n2" : {"type" : "integer"}
        }
    }
  )";

        std::string dataString = R"(
    {
	    "s1": "1",
	    "n2": 2,
        "x4": 4,
        "x5": 5
    }
  )";

        auto schema = jsoncons::jsonschema::make_json_schema(jsoncons::json::parse(schemaString));
        auto parsed = jsoncons::json::parse(dataString);

        schema.validate(parsed, reporter);

        ASSERT_EQ(2U, result.size());
        EXPECT_EQ("additionalProperties"s, result[0].keyword());
        EXPECT_EQ("/additionalProperties/x4"s, result[0].eval_path().string());
        EXPECT_EQ("/x4"s, result[0].instance_location().string());
        EXPECT_EQ("additionalProperties"s, result[1].keyword());
        EXPECT_EQ("/additionalProperties/x5"s, result[1].eval_path().string());
        EXPECT_EQ("/x5"s, result[1].instance_location().string());
    }

Include a small, self-contained example if possible

What compiler, architecture, and operating system?

Visual Studio 2022 on Windows 11,
Toolset: Visual Studio 2022 (v143),
C++ Language Standard: Preview - ISO C++23 Standard (/std:c++23preview)

What jsoncons library version?

• Latest release 1.4.3
• master

[danielaparker]

Fix is on master

[NiN9876]

Looks good, Thank you!