Upload a CSV (.csv) or Excel (.xlsx) file into OneSchema.
The file should be sent as multipart/form-data and include the filename and the file's media type.

If no embed_id is provided, the file is uploaded into the Workspaces product. Without a workspace_id, it goes into your default team workspace; pass a workspace_id to target a specific workspace. Provide embed_id only when you want to import the file into a specific Embed instead.