mail: reset PHPMailer encoding between wp_mail() calls

Author: R1shabh-Gupta

src/wp-includes/pluggable.php

@@ -358,6 +358,7 @@ function wp_mail( $to, $subject, $message, $headers = '', $attachments = array()
 		$phpmailer->clearReplyTos();
 		$phpmailer->Body    = '';
 		$phpmailer->AltBody = '';
+		$phpmailer->Encoding = PHPMailer\PHPMailer\PHPMailer::ENCODING_8BIT;
 
 		// Set "From" name and email.