feat: Add form validations and success message to contact form

[akshay0611]

Summary: This PR enhances the contact form by adding client-side validations and a success message. The changes aim to improve the user experience by ensuring valid inputs and providing feedback upon successful submission.

Changes Made:

• Added HTML5 validation attributes (pattern, minlength, maxlength) to enforce input constraints.
• Included a success message that appears dynamically after form submission.
• Implemented JavaScript to handle form validation, display the success message, and reset the form fields.

Testing:

• Verified that all fields are validated correctly.
• Tested responsiveness across different screen sizes.
• Ensured alignment with existing CSS styles and framework conventions.

Related Issue: Closes #8