MM-27525: Obscure Global Relay's SMTP password. (#15228)

* MM-27525: Obscures the Global Relay SMTP password.

* MM-27525: Desanitize global relay's SMTP password.

* MM-27525: Does not set the fake value if the field is blank.

model/config.go

@@ -3487,4 +3487,8 @@ func (o *Config) Sanitize() {
 	for i := range o.SqlSettings.DataSourceSearchReplicas {
 		o.SqlSettings.DataSourceSearchReplicas[i] = FAKE_SETTING
 	}
+
+	if o.MessageExportSettings.GlobalRelaySettings.SmtpPassword != nil && len(*o.MessageExportSettings.GlobalRelaySettings.SmtpPassword) > 0 {
+		*o.MessageExportSettings.GlobalRelaySettings.SmtpPassword = FAKE_SETTING
+	}
 }