See removing the field by using code is not possible however you can disable using the sale price across the store.
function custom_wc_get_sale_price( $sale_price, $product ) {
return $product->get_regular_price();
return $sale_price;
}
add_filter( 'woocommerce_get_sale_price', 'custom_wc_get_sale_price', 50, 2 );
add_filter( 'woocommerce_get_price', 'custom_wc_get_sale_price', 50, 2 );
For hiding this field you can use CSS to hide it from the product edit screen. But that CSS needs to be loaded on the admin side, so you can use this in theme style sheet may not work.
