How to add button as an icon to annotationPopup?

Product: PDF Webviewer

Product Version: Latest

Please give a brief summary of your issue:
I want to add new button to annotationPopup as an icon. I tried it like below code but it’s not work.

instance.UI.annotationPopup.add({
                type: 'actionButton',
                label: '<i class="bi bi-file-font"></i>', 
                onClick: () => console.log('clicked'),
            });

I found my own answer;

instance.UI.annotationPopup.add({
                type: 'actionButton',
                label: 'Comment',
                img: '<svg aria-hidden="true" focusable="false" data-prefix="fas" data-icon="file-arrow-up" class="svg-inline--fa fa-file-arrow-up" role="img" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 384 512"><path fill="currentColor" d="M256 0v128h128L256 0zM224 128L224 0H48C21.49 0 0 21.49 0 48v416C0 490.5 21.49 512 48 512h288c26.51 0 48-21.49 48-48V160h-127.1C238.3 160 224 145.7 224 128zM288.1 344.1C284.3 349.7 278.2 352 272 352s-12.28-2.344-16.97-7.031L216 305.9V408c0 13.25-10.75 24-24 24s-24-10.75-24-24V305.9l-39.03 39.03c-9.375 9.375-24.56 9.375-33.94 0s-9.375-24.56 0-33.94l80-80c9.375-9.375 24.56-9.375 33.94 0l80 80C298.3 320.4 298.3 335.6 288.1 344.1z"></path></svg>',
                onClick: () => console.log('clicked'),
            });