Use `DataOrCollectionRequestAdapter` as additional fetch data and data landing payload

[mvdbeek]

This would line it up with our workflow landing page payload, as well as our workflow test data definition.
There's a growing number of workflow authors that are likely even familiar with the syntax and could hit the ground running when writing custom upload things.

We should be able to transform DataOrCollectionRequestAdapter to the appropriate pydantic model internally if we want to just get this started for CreateDataLandingPayload only ...

[jmchilton]

Ahh... I missed this issue when reviewing the PR. Yes - I feel like this should be an option in that API - I would just add and vice versa 😅. I would think even if we just support the workflow format in data uploads - that would be a lot more palatable if the data fetch API supported the format also.

[mvdbeek]

Agreed, for the fetch data API addition makes sense. I would rather like to avoid the complexity of having both request shapes available in the data landing API, but we could add a file landing API endpoint if you're more comfortable with that ?