V15: Order children by sortorder

[Zeegaan]

Fixes #17844

Notes

• Orders children by their sortorder.
• This is only a feature for children, so does not apply to descendants/ancestors etc.

How to test

• Create a doc type called child, with a property textstring called "Title"

• Create a doc type called root, with allow as root set to true, and the "child" doc type allowed as child.

• Create this structure in your content:

• Root

  • Child One
  • Child Two
  • Child Three
  • Child four

• Now swap the order, by clicking on root and selection the action "sort children"

• You can then use a controller, or somewhere other, where you call the .Children on your root node,

• I did this by creating a controller, and calling https://localhost:44339/test/index via postman

using Microsoft.AspNetCore.Mvc;
using Umbraco.Cms.Core.PublishedCache;
using Umbraco.Cms.Core.Services;

namespace Umbraco.Cms.Web.UI;

[ApiController]
[Route("[controller]/[action]")]
public class TestController : Controller
{
    private readonly IPublishedContentCache _publishedContentCache;

    public TestController(IPublishedContentCache publishedContentCache)
    {
        _publishedContentCache = publishedContentCache;
    }

    [HttpGet]
    public async Task<IActionResult> Index()
    {
        var content = await _publishedContentCache.GetByIdAsync(new Guid("´{INSERT YOUR ROOT NODE KEY HERE}"));
        var children = content?.Descendants();
        return Ok(children?.Select(x => x.Name));
    }
}

[nikolajlauridsen]

LGTM 👍