Error in add product function

### Description of issue
Once the product is added. If we click again to add the product it shows "Are you sure to add the product ". Instead it should say "The product is already added".

```
Path: /pages/products/myproduct.html
Browser: Chrome 112.0.0.0 on Windows 10
Viewport: 1504 x 860 @1.5x
Language: en-US
Cookies: Enabled
```

[Open in BrowserStack](https://www.browserstack.com/user/try-live?url=https%3A%2F%2Fdeploy-preview-2--tharas-world.netlify.app%2Fpages%2Fproducts%2Fmyproduct.html&os=Windows&os_version=10&browser=Chrome&browser_version=112.0&resolution=1504x860&speed=1&start=true&ref=netlify-source)

Submitted from [Netlify Deploy Preview #2](https://deploy-preview-2--tharas-world.netlify.app/pages/products/myproduct.html)

Open pages/products/myproduct.html and reproduce the issue by adding a product, then clicking to add it again. Done means the second attempt displays "The product is already added" instead of the current confirmation message; verify the behavior in Chrome on the listed page.

Written by the indexing model from the issue text.