.circleci: Remove ingest state diff job from CircleCI

[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

Remove ingest state diff job from CircleCI

Why

We are running the state diff job as kubernetes cron job every 15 minutes. The CircleCI job seems to be much more flaky than the kubernetes cronjob.

[leighmcculloch]

It's sad that we lose visibility of a clear this commit caused this failure, but given how flaky this is it's not like we get that signal now.

Where do we see the test run on Kubernetes? [Edit: I found where it is setup.]

[ire-and-curses]

@leighmcculloch this was never a great place for this test. New code could fail on a ledger in the past, or in the future, so the choice of current ledger during the build step is arbitrary and doesn't provide good coverage. That's why we switched to the k8s approach.