You can't lose something that your iPad has never had...
The Wallet App is unique to iPhone due to hardware…
The iPhone Wallet uses NFC to wirelessly communicate with physical Point of Sale (PoS) terminals - NFC being the mechanism used by ApplePay (and Google’s Android equivalent) to securely exchange registered Credit Card details and authorise a payment.
The Apple Wallet App has dependency upon NFC hardware which is absent from all models of iPad. Consequently, the Wallet App is not available for iPad. Whilst perhaps a moot point, consider the practicalities of attempting to bring a specific area of an iPad (which may be sizeable) within close range of a PoS terminal!
Whilst iPad does not have a Wallet App per-se, iPad does have Wallet in iPad settings. Here you can register Credit Cards for ApplePay - but this is not intended for NFC. Instead, iPad is able to participate in remote e-commerce payments - such as a website.