PMPro: Show the next payment date instead of the expiration date for the !!membership_expiration!! email var if it's blank.

my_email_var_membership_expiration.php

<?php
/**
 * Show the next payment date instead of the expiration date
 * for the !!membership_expiration!! email var if it's blank.
 * Add this code into a custom plugin or Code Snippet.
 * More information on how to add code snippets here: https://www.paidmembershipspro.com/how-to-add-code-to-wordpress/
 */
function my_email_var_membership_expiration( $data, $email ) {
	if ( empty( $data['membership_expiration'] ) ) {
		$user = get_user_by( 'email', $data['user_email'] );
		if ( ! empty( $user ) ) {
			// We want to ping the gateways when we check for the next payment date.
			add_filter('pmpro_next_payment', array('PMProGateway_paypalexpress', 'pmpro_next_payment'), 10, 3);
			add_filter('pmpro_next_payment', array('PMProGateway_stripe', 'pmpro_next_payment'), 10, 3);
			
			$next_payment = pmpro_next_payment( $user->ID );
			if ( ! empty( $next_payment ) ) {
				$data['membership_expiration'] = '<p>Your next payment will be on ' . date_i18n( get_option( 'date_format' ), $next_payment ) . '.</p>';
			}						
		}
	}
	
	return $data;
}
add_filter( 'pmpro_email_data', 'my_email_var_membership_expiration', 10, 2 );