WordPress: Only load JS + CSS if a Contact Form 7 form is used

functions.php

<?php
function customize_cf7_dequeue() {
	wp_dequeue_script( 'contact-form-7' );
	wp_dequeue_style( 'contact-form-7' );
}
add_action( 'wp_enqueue_scripts', 'customize_cf7_dequeue' );

function customize_cf7_enqueue( $content ) {
	if ( has_shortcode( $content, 'contact-form-7' ) ) {
		wpcf7_enqueue_styles();
		wpcf7_enqueue_scripts();
	}
	return $content;
}
add_filter( 'the_content', 'customize_cf7_enqueue' );