Hi there and welcome
Its a trick they do to make you believe this is the case, but being an iPad it cannot be infected (due to how they worked).
One thing though is t is best to remove the cache data.
So go to In the Settings app, tap Safari, and you will see options to Clear History and Clear Cookies and Data.
This will ensure the page trying to trick you is gone.
If you would like any additional information or assistance, please do not hesitate to let me know.
Else if you can take a second to rate my service by clicking one of the stars at the top of the screen then submit, that would be greatly appreciated.