Extend JSON file reader to handle array of objects with resourceSpans

[Adarsh-jaiss]

Which problem is this PR solving?

• Resolves #2225

Description of the changes

• This commit updates the JSON file reader function to handle an array of JSON objects containing 'resourceSpans' arrays. It now merges these arrays into a single 'resourceSpans' array before processing, ensuring compatibility with both single JSON objects and arrays of objects.

Checklist

• [x] I have read https://github.com/jaegertracing/jaeger/blob/master/CONTRIBUTING_GUIDELINES.md
• [x] I have signed all commits
• [ ] I have added unit tests for the new functionality
• [x] I have run lint and test steps successfully
  • for jaeger: make lint test
  • for jaeger-ui: yarn lint and yarn test