remove depraction of validateEmailAddress

for there are legit use cases to validate an email address without
sending there to

Signed-off-by: Arthur Schiwon <blizzz@arthur-schiwon.de>

lib/public/Mail/IMailer.php

@@ -96,8 +96,6 @@ interface IMailer {
 	public function send(IMessage $message): array;
 
 	/**
-	 * @deprecated 26.0.0
-	 *
 	 * @param string $email Email address to be validated
 	 * @return bool True if the mail address is valid, false otherwise
 	 * @since 8.1.0