Password toggle visibility

[Gaurav-Kumar-1907]

This pull request adds the Password Visibility Toggle feature to the ViBe LMS authentication pages (Sign In and Sign Up).
The enhancement allows users to view or hide their password while typing, improving usability and reducing login/signup errors caused by typos.

Key Changes:

• Added an eye / eye-off icon inside password input fields.
• Created independent useState hooks for Sign In and Sign Up forms to manage toggle state separately.
• Toggling the icon switches the input type between password (hidden) and text (visible).
• Fully frontend implementation; no backend changes required.
• Works seamlessly on both desktop and mobile devices.

Benefits:

• Reduces password typing errors.
• Improves user experience and accessibility.
• Maintains backend security and authentication flow.

I have also added two images above. At first the password it not visible to user. Whereas when eye icon is pressed then password gets visible in the next image.