services/horizon/internal/ingest: Add missing tables to TruncateIngestStateTables()

[tamirms]

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 name of package that is most changed in the PR, ex.
  services/friendbot, or all or doc if the changes are broad or impact many
  packages.

Thoroughness

• This PR adds tests for the most critical parts of the new functionality or fixes.
• I've updated any docs (developer docs, .md
  files, etc... affected by this change). Take a look in the docs folder for a given service,
  like this one.

Release planning

• I've updated the relevant CHANGELOG (here for Horizon) if
  needed with deprecations, added features, breaking changes, and DB schema changes.
• I've decided if this PR requires a new major/minor version according to
  semver, or if it's mainly a patch change. The PR is targeted at the next
  release branch if it's not a patch change.

What

The contract_asset_balances and contract_asset_stats tables were missing from TruncateIngestStateTables() which means that those tables would not get cleared during state rebuilds. It is necessary for all tables which hold ledger entries to be truncated in TruncateIngestStateTables() otherwise state rebuilds may fail because Horizon can try to insert rows that already exist in the state tables which would result in a duplicate key errors from postgres.

Known limitations

[N/A]