Custom button(from different plugin) in EA Advanced accordion widget

Hi!

Thank you for such an awesome plugin.

I was wondering if there is way to add a custom button in one of the widgets(EA Advanced Accordion widget)
I wanted to add a button( from a different plugin-document gallery) which appears in the classic editor but I want it in the EA Advanced accordion widget as well. From the support forums of the document gallery plugin, I found out that to insert that button in the classic editor, we need to paste the code in the functions.php file of the wordpress theme. But I don’t exactly know where to paste the code so that the button appears in the elementor addon widget. The code is as follows:

function dg_specific_button_js() { ?>
<script type="text/javascript">
    function open_dg_tab() {
        if ( this.frame === undefined ) {
            if ( wp.media.frame !== undefined && jQuery.inArray(wp.media.frame.state().id, ['dg', 'dg-edit', 'dg-library'])<0 ) {
                wp.media.frame.setState('dg');
            }
            var options = {
                frame: 'post',
                state: 'dg',
                title: DGl10n.dgMenuTitle,
                multiple: true
            };
            this.frame = wp.media.editor.open(null, options);
        } else {
            if ( jQuery.inArray(this.frame.state().id, ['dg', 'dg-edit', 'dg-library'])<0 ) {
                this.frame.setState('dg');
            }
            this.frame.open();
        }
        return false;
    }
    jQuery(document).ready( function() {
        if ( typeof wp.media.collection !== 'function' ) return;
	jQuery('#dg-specific-button').removeAttr('disabled').click(open_dg_tab);
    } );
</script>
<?php }
function dg_check_page_type( $hook ) {
    if ( in_array( $hook, array( 'post.php', 'post-new.php' ), true ) ) {
        function dg_add_specific_button() {
            echo '<button id="dg-specific-button" class="button" disabled>'.__( 'Create Document Gallery', 'document-gallery' ).'</button>';
        }
        add_action('media_buttons', 'dg_add_specific_button');
        add_action('admin_print_footer_scripts', 'dg_specific_button_js');
    }
}
add_action('admin_enqueue_scripts', 'dg_check_page_type');

Thank you and sorry for the trouble.