Is your feature request related to a problem? Please describe.
The legacy onepassword-connect provider supported fetching multiple fields of a single item, via dataFrom.extract for example. The new onepasswordsdk provider, introduced in #4628, does not support this.

Describe the solution you'd like
Add support for fetching multiple or all fields of a vault item.

Describe alternatives you've considered
Fetch each vault item field explicitly and update this list whenever a field is added or removed. High maintenance cost.