fix: OnCompleted stops dialogues working in FluentInputFile

[ApacheTech]

🐛 Bug Report

If you try to use dialogues within the OnCompleted task of a FluentInputFile component, the buttons within the dialogue do not respond.

💻 Repro or Code Sample

This assumes that <FluentDialogProvider /> is added within MainLayout.razor or App.razor.

@page "/sandbox"

<h3>
    @_message
</h3>

<FluentStack HorizontalGap="4">
    <FluentButton OnClick="ShowConfirmationAsync" Appearance="Appearance.Accent">
        Show Confirmation Directly
    </FluentButton>
    <FluentButton Id="btnUpload" Appearance="Appearance.Accent">
        Upload Then Confirm
    </FluentButton>
</FluentStack>

<FluentInputFile Class="h-fit w-full"
                 Multiple="false"
                 AnchorId="btnUpload"
                 Mode="InputFileMode.Stream"
                 MaximumFileSize="@(1024 * 1024 * 1024)"
                 DragDropZoneVisible="false"
                 OnCompleted="OnFileUploadedAsync" />

@code {
    private string _message = "Ready.";

    [Inject]
    private IDialogService Dialogue { get; init; }

    private async Task OnFileUploadedAsync(IEnumerable<FluentInputFileEventArgs> args)
    {
        await ShowConfirmationAsync();
    }

    private async Task ShowConfirmationAsync()
    {
        var dialogue = await Dialogue.ShowConfirmationAsync("Do you want to continue?");
        var result = await dialogue.Result;
        _message = result.Cancelled
            ? "Cancelled"
            : "Accepted";
    }
}

🤔 Expected Behavior

Whether the confirmation dialogue is shown via OnClick from FluentButton, or OnComplete from FluentInputFile, both should allow the dialogue to be responsive.

😯 Current Behavior

The above code sample shows that the buttons within the dialogue are unresponsive, if called via the OnCompleted task.

💁 Possible Solution

Could the OnCompleted task be detached from the page dispatcher, requiring an InvokeAsync wrapper to reattach it?

🔦 Context

One of our services is Partially Automated Workflows, where the user uploads a file, and needs to confirm that they wish to continue if there are any chargable items within the workflow. This issue stops that process from working.

🌍 Your Environment

• OS & Device: Windows 11 Enterprise
• Browser: Tested on Firefox, Edge, Opera, Chrome, and Maxathon
• Framework Version: net8.0
• Blazor App: Global InteractiveServer
• Fluent UI Blazor library Version: 4.11.4