Add Success Message to Newsletter Form

[akshay0611]

Problem: The current newsletter form does not provide feedback to users after they subscribe. This can lead to confusion about whether their submission was successful.

Proposed Solution:

• Add a success message that appears after the user submits the form.
• Use JavaScript to dynamically display the success message upon form submission.

Expected Outcome: A more user-friendly newsletter form that confirms successful subscriptions, improving the overall user experience.