Add comprehensive tests for mentor repository and authentication

- Implemented tests for creating, retrieving, updating, and deleting mentors in `mentor_repository_test.rs`.
- Added tests for user authentication, including successful login, invalid email formats, and inactive users in `auth_login_tests.rs`.
- Created a mock test environment setup in `mock_test.rs` to facilitate database operations during tests.
- Updated module structure to include new test files for mentors and authentication.
- Ensured cleanup of the database after tests to maintain isolation and prevent side effects.

imphnen-entities/src/common_dto.rs

@@ -1,9 +1,5 @@
 use serde::{Deserialize, Serialize};
-use surrealdb::{
-	engine::local::Db,
-	engine::any::Any,
-	Surreal,
-};
+use surrealdb::{Surreal, engine::any::Any, engine::local::Db};
 use utoipa::{IntoParams, ToSchema};
 
 #[derive(Debug, Clone, Serialize, Deserialize, ToSchema)]