Electro display brand text instead of brand logo in single product page

functions.php

if ( ! function_exists( 'electro_template_single_brand' ) ) {
	/**
	 * 
	 */
	function electro_template_single_brand() {

		global $product;
	
		$product_id = electro_wc_get_product_id( $product );
		$brands_tax = electro_get_brands_taxonomy();
		$terms 		= get_the_terms( $product_id, $brands_tax );
		$brand_img 	= '';

		if ( $terms && ! is_wp_error( $terms ) ) {
			
			foreach ( $terms as $term ) {
				$thumbnail_id 	= get_woocommerce_term_meta( $term->term_id, 'thumbnail_id', true );

				$brand_img 	.= '<a href="' . esc_url( get_term_link( $term ) ). '"><span>' . esc_attr( $term->name ) . '</span>';
				
			}
		}

		if ( ! empty( $brand_img ) ) : ?>
		<div class="brand">
			<?php echo wp_kses_post( $brand_img ); ?>
		</div>
		<?php endif;
	}
}