Add the ability to make the progress bar blocking on the image uploader widget

Currently if you want to upload an image to a file document you will most likely use the image-uploader widget, but with slower internet (3-4g on mobile devices) uploading can take a few seconds. The widget itself shows a non blocking progress bar, which means the user can still press buttons, go to different pages etc, which can result in errors with committing the image. I think it would be good if there was an option in the widget to make this progress bar blocking to prevent users from getting an error. 

For now we have a workaround where we use a HTMLsnippet that runs javascript with jquery to if a non blocking progress bar is present, a blocking underlay is added.

$(document).ready(function() {
    let interval = setInterval(function() {
        // Check if div with class "mx-progress mx-progress-empty" exists
        let targetDiv = $('.mx-progress.mx-progress-empty');
        
        if (targetDiv.length > 0) {
            // If not already added, append the mx-underlay div to the parent
            targetDiv.each(function() {
                let parent = $(this).parent();
                if (parent.find('.mx-underlay').length === 0) {
                    parent.append('<div class="mx-underlay"></div>');
                }
            });
        } else {
            // Remove the mx-underlay div if mx-progress mx-progress-empty is not found
            $('.mx-underlay').remove();
        }
    }, 500); // Run every 500ms
});