refactor(lovescape): update availability logic to infer email status via username validation

[kaifcodec]

• Refined logic in lovescape.py to improve accuracy for email availability checks.
• Updated the error handling flow to correctly interpret "Username is already used" API responses.
• Leveraged the API's validation sequence: if the "email already used" check passes but the username check triggers, the email is confirmed as not registered.
• Enhanced reliability of the module by correctly mapping API error responses to Result.available status.

[json-hunter07]

@kaifcodec Yeah it is now correctly handling the validation.
It seems like the site had changed their sign up logic.
Merging it!