V10: merge v8 blobstorage file deletion fix

[Zeegaan]

This is a v10 port of #11998

How to test in v10

• Create a storage account, and a blob container
• In your Appsettings, add the Storage:AzureBlob (paste in your connection string and container name from step 1)

"Umbraco": {
    "Storage": {
      "AzureBlob": {
        "Stylesheets": {
          "ConnectionString": "yourConnectionStringHere",
          "ContainerName": "BlobContainerNameHere"
        }
      }
    },

• Add the Umbraco.StorageProvider.AzureBlob nuget package to the Web.UI project
• In your startupcs in the ConfigureServices method, add AddAzureBlobFileSystem like this:

services.AddUmbraco(_env, _config)
                .AddBackOffice()
                .AddWebsite()
                .AddComposers()
                .AddAzureBlobFileSystem("Stylesheets", options => options.VirtualPath = "~/css")
                .Build();

• Create a composer to swap out the PhysicalFileSystem for the Stylesheets to blobstorage:

using Umbraco.Cms.Core.Composing;
using Umbraco.Cms.Infrastructure.DependencyInjection;
using Umbraco.StorageProviders.AzureBlob.IO;

namespace Umbraco.Cms.Web.UI;

public class MyComposer : IComposer
{
    public void Compose(IUmbracoBuilder builder)
    {
        builder.ConfigureFileSystems((provider, fileSystems) => fileSystems.SetStylesheetFilesystem(provider.GetRequiredService<IAzureBlobFileSystemProvider>().GetFileSystem("Stylesheets")));
    }
}

• You should now be able to run Umbraco
• Create a stylesheet, assert it shows up in your blob container, and is not saved locally
• Delete the stylesheet, assert it actually gets deleted from your blob container.

[elit0451]

Works as expected 💪 will merge it in shortly