Modified and deleted some files

[Prabhasharma]

Hello Friend!

I have made the following changes in this PR:

Removed Unnecessary Files: Deleted "26 - Stripe Follow Along Nav/index-START.html" and "27 - Click and Drag/index-START.html" as they were redundant. Updated Existing Files: Modified "29 - Countdown Timer/index.html" to improve code clarity. In the "30 - Whack A Mole" folder, updated "index-FINISHED.html" and removed "index-START.html" to clean up the project. Updated "30 - Whack A Mole/style.css" for better styling consistency. These changes help streamline the repository and ensure that the code stays consistent with the video content. Minor modifications like these are intended to improve readability without altering the core functionality.

Feel free to review and merge if everything looks good!