chore(sogo-ealarms-notify): improve arguments parsing

Fixes #5197

SoObjects/SOGo/SOGoMailer.h

@@ -42,7 +42,7 @@
 + (SOGoMailer *) mailerWithDomainDefaults: (SOGoDomainDefaults *) dd;
 
 - (id) initWithDomainDefaults: (SOGoDomainDefaults *) dd;
-
+- (BOOL) requiresAuthentication;
 - (NSException *) sendMailData: (NSData *) data
 		  toRecipients: (NSArray *) recipients
 			sender: (NSString *) sender

SoObjects/SOGo/SOGoMailer.m

@@ -181,6 +181,11 @@
   [super dealloc];
 }
 
+- (BOOL) requiresAuthentication
+{
+  return ![mailingMechanism isEqualToString: @"sendmail"] && authenticationType;
+}
+
 - (NSException *) _sendmailSendData: (NSData *) mailData
 		       toRecipients: (NSArray *) recipients
 			     sender: (NSString *) sender