Add definition of additional fields in history ledger table

[amishas157]

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 docs and README with the added features, breaking changes, new instructions on how to use the repository.

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

When I created this earlier PR #57, I missed adding definition of additional fields in source file. This is why the definitions were not reflected on dbt docs.

After adding changes this PR, the docs look good

Why

Covered above

Known limitations

To check with Simon/Syd, if these tests make sense or not.

[amishas157]

Unsure if these test config apply to these 3 fields

[sydneynotthecity]

They apply to node_id and signature, but idk how soroban_fee_write_1kb is handled for old data. I think it would be aggressive for us to add a null check to that field.

[amishas157]

Got it. Gonna 🔪 it

[sydneynotthecity]

LGTM

General note: if you want this PR to follow semvar for releases, you'll need to add patch/* to your branch name so that the release is tagged appropriately. Changes are good