I believe there aren't any first-party PaaS offerings for this and Azure Firewall doesn't have the ability to scan file uploads either. You could however build your own pipeline to scan file uploads before processing them.
To scan the files, you could leverage one of the logic app connectors available for virus scanning but note that these rely on external services to perform the scanning. A customer solution would involve using an open-source engine like ClamAV that you could call from Azure Functions for example. This blog shows how you can approach this.
To ensure infected files never reach your internal storage, you could first store it in a temporay blob container, scan it and then move it to the actual location where you need it for processing.