[Fix] Handle Custom Response for Incorrect Credentials

[adkif]

Description

Currently, when users provide incorrect credentials during login, the backend API response is displayed directly in the UI. This is not user-friendly and could expose sensitive implementation details. We need to intercept this response and display a custom error message instead.

Acceptance Criteria

1. Replace the raw backend error response with a user-friendly error message like:

“Invalid username or password. Please try again.”

2. Ensure error messages are localized (if i18n is in use).
3. Handle all edge cases such as:

Incorrect format of backend error response.
Network issues or timeouts.

4. Maintain consistency in UI design for error messages (e.g., use Nebular toastr).

Note

Ensure the HTTP interceptor (if used) does not override this custom message.
The existing login service should handle the backend response and emit the custom message via error-handling logic.