Add json field to operations export

[chowbao]

PR Checklist

PR Structure

• This PR has reasonably narrow scope (if not, break it down into smaller PRs).
• This PR avoids mixing refactoring changes with feature changes (split into two PRs
  otherwise).
• This PR's title starts with the jira ticket associated with the PR.

Thoroughness

• This PR adds tests for the most critical parts of the new functionality or fixes.
• I've updated the README with the added features, breaking changes, new instructions on how to use the repository. I updated the description of the fuction with the changes that were made.

Release planning

• I've decided if this PR requires a new major/minor/patch version accordingly to
  semver, and I've changed the name of the BRANCH to release/_ , feature/_ or patch/* .

What

Add JSON blob of operation.details

Why

To leverage BigQuery JSON data type as well as aid downstream dbt models

Known limitations

• Need to test in test-hubble

[sydneynotthecity]

LGTM

[sydneynotthecity]

This is gonna be obnoxious to maintain. I'll start communicating the changes to external partners so we can work on dropping the extra OperationDetailsJSON

[chowbao]

Yeah. Our unit tests are a pain in general unfortunately