unstructured

570ee078 - fix: throw validation error when json is passed with invalid unstructured json (#4002)

fix: throw validation error when json is passed with invalid unstructured json (#4002) ### Notes Adds validation if `json` / `ndjson` are not valid unstructured schema. ### Testing Manually tested serverless API with example json: ``` test_length = [] = 200 test_invalid = [{"invalid": "schema"}] = 422 test_invalid_ndjson ={"hi": "there"} = 422 test_chunk = [{"type":"Header","element_id":"a23fdadef9277f217563e217ebd074d5" ... = 200 ```