Electro - Remove Uncategorized category in Store Directory

function.php

add_filter( 'woocommerce_product_categories_widget_args', 'el_child_exclude_uncategory' );

function el_child_exclude_uncategory( $cat_args ) {
    $cat_args['exclude'] = get_option( 'default_product_cat' );

    return $cat_args;
}