OO-4529 render mail-not-sent message as error and not as info dialog

src/main/java/org/olat/admin/user/SendTokenToUserForm.java

@@ -181,7 +181,7 @@ public class SendTokenToUserForm extends FormBasicController {
 		if(result.getReturnCode() == 0) {
 			showInfo("email.sent");
 		} else {
-			showInfo("email.notsent");
+			showError("email.notsent");
 		}
 	}
 }
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