Add functionality to hide ingestion enabled flag from --help output

[aditya1702]

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

Closes #4906

• Add a new Hidden config option which makes it easy to hide flags from our --help output.
• Hide the flag: --exp-enable-ingestion-filtering since it is now enabled by default.
• Give a DEPRECATION warning if a user still specifies the flag.
• Integration tests to test the change.

Why

Ingestion filtering is now always enabled and does not require user specified flag.

Known limitations

[TODO or N/A]

[urvisavla]

Overall it looks good to me. Would be good to get another set of 👀 to review it as well. Also, there are a few linter warnings, it'll be great if you could address those as well. Thanks!

[urvisavla]

Please add a changelog entry to reflect this change. Also, we need to update the public documentation for ingestion filtering with these modifications.

[sreuland]

@aditya1702 , you can add Closes #4906 in the pr description, and then GH will automatically link the issue to this PR and also migrate the status of the issue to closed when the pr merges.

[sreuland]

looks good, left a few minor comments on test coverage, thanks for evaluating the feedback.