fix: update test_json to not use auto partition (#1187)
Update `test_json` to not use auto partition due to dependencies. Previously, to run `test_json` requires full requirements installation library to read file types, including but not limited to, docx, pptx, as well as others. Therefore the test will raise error with base installation. With the update, this fix also add to other test files to check its invariant with `elements_to_json`.
