fix: stringify json file

[sabhas]

Issue

closes #331

Intent

• when API sends a JSON file in response, It's treated as a JSON object on the frontend. So, stringify the response data before setting it to file content.

Checks

• [ ] Code is formatted correctly (npm run lint:fix).
• [ ] Any new functionality has been unit tested.
• [ ] All unit tests are passing (npm test).
• [ ] All CI checks are green.
• [ ] Reviewer is assigned.

[sasjsbot]

:tada: This PR is included in version 0.28.3 :tada:

The release is available on:

• GitHub release
• v0.28.3

Your semantic-release bot :package::rocket: