Fixed problems indicated by the mentor. Simplified return to one line

src/main/java/mate/academy/service/AuthenticationService.java

@@ -16,11 +16,7 @@ public class AuthenticationService {
     private final UserService service = new UserService();
 
     public boolean login(String email, String password) {
-
         User user = service.findByEmail(email);
-        if (user != null) {
-            return user.getPassword().equals(password);
-        }
-        return false;
-    }
+        return user != null && user.getPassword().equals(password);
+     }
 }