[BUGFIX] Fix from name and address fallback priority

Classes/Service/MailTemplateService.php

@@ -831,11 +831,17 @@ class MailTemplateService {
 	 */
 	private function loadTemplateValues($template): void {
 		$fromName = \trim($template->getFromName());
+		if ($fromName === '') {
+			$fromName = $this->fromName;
+		}
 		if ($fromName === '' && $GLOBALS['TYPO3_CONF_VARS']['MAIL']['defaultMailFromName']) {
 			$fromName = $GLOBALS['TYPO3_CONF_VARS']['MAIL']['defaultMailFromName'];
 		}
 
 		$fromMail = \trim($template->getFromMail());
+		if (!filter_var($fromMail, FILTER_VALIDATE_EMAIL)) {
+			$fromMail = $this->fromAddress;
+		}
 		if (!filter_var($fromMail, FILTER_VALIDATE_EMAIL)) {
 			$fromMail = $GLOBALS['TYPO3_CONF_VARS']['MAIL']['defaultMailFromAddress'];
 			if (!filter_var($GLOBALS['TYPO3_CONF_VARS']['MAIL']['defaultMailFromAddress'], FILTER_VALIDATE_EMAIL)) {