FormPrePopulateNotification - file upload doesn't work

[nexwork-percy]

When you register even a dummy, empty FormPrePopulateNotification handler, any form with a File Upload will not work.

Reproduction

Setup a new empty project

dotnet new -i Umbraco.Templates::13.5.2
dotnet new umbraco -n "FormsPrePopulateBug"
dotnet new sln -n FormsPrePopulateBug
dotnet sln add .\FormsPrePopulateBug\FormsPrePopulateBug.csproj
dotnet add Umbraco.Forms::13.3.0

Add a FormPrePopulateNotificationHandler

public class FormsComposer : IComposer
{
    /// <summary>
    /// Register event handlers for Umbraco Forms.
    /// <see href="https://docs.umbraco.com/umbraco-forms/developer/extending/adding-an-event-handler" />
    /// </summary>
    /// <param name="builder"></param>
    public void Compose(IUmbracoBuilder builder)
    {
        builder.AddNotificationHandler<FormPrePopulateNotification, FormsPrePopulateNotificationHandler>();
    }
}

public class FormsPrePopulateNotificationHandler : INotificationHandler<FormPrePopulateNotification>
{
    public void Handle(FormPrePopulateNotification notification)
    {
        // Empty
    }
}

Create a form and name it 'Test Form' with a File Picker.
Create a doctype and name it 'Home', allow Root, add a Form Picker and name it 'A Form', and allow the 'Test Form' to be picked.
Home can have a very simple template:

@using Umbraco.Cms.Web.Common.PublishedModels;
@inherits Umbraco.Cms.Web.Common.Views.UmbracoViewPage<ContentModels.Home>
@using ContentModels = Umbraco.Cms.Web.Common.PublishedModels;
@{
	Layout = null;
}

@await Component.InvokeAsync("RenderForm", new { formId = @Model.AForm, includeScripts = true })

Specifics

Using Umbraco 13.5.2
Umbraco.Forms 13.3.0

When commented out the line builder.AddNotificationHandler<FormPrePopulateNotification, FormsPrePopulateNotificationHandler>();, the File Upload works.

When not commented out, the file upload does not work.

Expected result

Form Entry contains the uploaded file.

Actual result

Form Entry does not contain the uploaded file.

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This item has been added to our backlog AB#46015