SendMailService does not send mails, mail validation is called wrong

[rengaw83]

Before an mail is send, the address is validated:

powermail/Classes/Domain/Service/Mail/SendMailService.php

Lines 99 to 102 in 40c6b72

	if (GeneralUtility::validEmail($email['receiverEmail'] === false) ||
	GeneralUtility::validEmail($email['senderEmail']) === false) {
	return false;
	}

The validation of the receiverEmail is always wrong: GeneralUtility::validEmail($email['receiverEmail'] === false). GeneralUtility::validEmail is always called with a bool value, not the mail address.
The bracket is incorrectly placed.

The bug exists since version 11/12 and was integrated in
11b7b14#diff-2d5d4d02fe84a8e6e4354363868cb6218f61c804b9d3e6ac6423cb75874028fdR97-R98

[rengaw83]

With the Following fix the mail send works like expected again:

- if (GeneralUtility::validEmail($email['receiverEmail'] === false) || 
+ if (GeneralUtility::validEmail($email['receiverEmail']) === false || 
     GeneralUtility::validEmail($email['senderEmail']) === false) { 
     return false; 
 }
 if (empty($email['subject'])) {
      // don't want an error flashmessage
      return true;
 }
 return $this->prepareAndSend($email);

I have created an PR for that: #1113