Allow adding the standard umbraco styling (header and border) into the block preview

[mistyn8]

Standard grid looks like this, with clear delineation for content and indication of block element.

BlockPreview could look like:

This is achievable with the response enricher:

using Umbraco.Cms.Core.Models.PublishedContent;
using Umbraco.Cms.Core.Services;
using Umbraco.Community.BlockPreview.Interfaces;

namespace Lovell.Web.Extensions.BlockPreview
{
    public class BlockPreviewResponseEnricher : IBlockPreviewResponseEnricher
    {

        private readonly IContentTypeService _contentTypeService;

        public BlockPreviewResponseEnricher(IContentTypeService contentTypeService)
        {
            _contentTypeService = contentTypeService;
        }

        public Task<string> EnrichAsync(
            string markup,
            HttpContext httpContext,
            IPublishedContent? content,
            string? blockEditorAlias = null,
            string? contentElementAlias = null,
            string? contentUdi = null,
            string? settingsUdi = null,
            int? blockIndex = null)
        {

            var ct = _contentTypeService.Get(contentElementAlias ?? string.Empty);

            // ct.Icon can be "icon-plugin color-purple" using umb-icon translates that correctly for us
            string contentElementIcon = ct?.Icon ?? "icon-plugin";
            string contentElementName = ct?.Name ?? contentElementAlias ?? "Block";
            
            return Task.FromResult(WrapMarkup(markup, contentElementName, contentElementIcon));

        }

        private string WrapMarkup(string innerHtml, string? alias, string? icon)
        {
            return $@"<div style=""border-radius: var(--uui-border-radius, 20px);border: 1px solid var(--uui-color-border, #d8d7d9);"">
                        <umb-ref-grid-block>
                            <umb-icon slot=""icon"" name=""{icon}""></umb-icon>
                            <span slot=""name"">{alias}</span>                            
                        </umb-ref-grid-block>
                        {innerHtml}
                    </div>";
        }
    }
}

However, this might be better handled upstream in the lit web component (and allow ufm label support) and avoid those calls to the contentTypeService.
An accompanying options toggle could leave the default as no decoration.