Add Success Message for Newsletter Subscription with Auto-dismiss Functionality

[akshay0611]

Problem

There was no success message displayed after a user subscribes to the newsletter. This update addresses that issue.

Solution

1. Added a success message that shows up upon form submission, thanking the user for subscribing.
2. Used JavaScript's setTimeout() function to automatically hide the success message after 4 seconds.
3. Ensured the success message is hidden by default and only shown after successful submission.

Testing

• Test the subscription form by entering a valid email.
• Ensure the success message appears after submission and disappears after 4 seconds.

This update improves the user experience by providing immediate feedback to the user upon submitting their email and it closes the Issue No #4 .