SLATE: "secure-upload" and "secure-upload-raw" source not found in Slate

Hi, I’ve been working with a Slate Public Application. When I try to add a “New Query”, I get the following error:

“Data source not found, contact your Palantir administrator to configure data sources.”

The documentation mentions that the secure-upload and secure-upload-raw-oauth data sources are required, but I cannot find these sources in my environment.

I’m using the free Palantir Dev environment. Could someone please help me understand whether these data sources are available in the free Dev version, and if not, what the recommended approach is for configuring Slate Public?