Improve Error Handling, Validation, and UI Feedback in src/Front_end/Authentication/loginpage/loginbox.jsx

[Amansingh0807]

The current Login component has some issues that impact user experience and error handling:

1. Missing Input Validation: There's no check for empty email or password fields before attempting login.
2. Error Handling: Errors in CheckemailExists and PasswordCheck are not properly handled, which can lead to unexpected behavior if these functions fail.
3. Loading Indicator: There is no loading state during login, leading to potential multiple submissions and user confusion.
4. User-Friendly OAuth Errors: Errors during OAuth login lack clear, user-friendly messages.

Suggested Fixes:

• Add input validation for empty email and password fields.
• Wrap calls to CheckemailExists and PasswordCheck in try-catch blocks.
• Implement a loading state to disable the login button while processing.
• Display clear error messages if OAuth login fails.