chore(parse_groks): expose internal errors

[neuronull]

Summary

parse_grok follows the Datadog Log's Grok algorithm's behavior where errors in applying filters are non fatal.
This change surfaces those filter errors to the caller, and differentiates between fatal and non fatal, as outlined by the Datadog Log's Grok algorithm, allowing the caller to decide whether to align with that or differ.

The stdlib parse_groks was unmodified, as such this is not a change to user facing behavior. If we decide to change that, we can do it in a follow up change.

Change Type

• Bug fix
• New feature
• Non-functional (chore, refactoring, docs)
• Performance

Is this a breaking change?

• Yes
• No

How did you test this PR?

Added/corrected unit tests

Does this PR include user facing changes?

• Yes. Please add a changelog fragment based on
  our guidelines.
• No. A maintainer will apply the "no-changelog" label to this PR.

Checklist

• Our CONTRIBUTING.md is a good starting place.
• If this PR introduces changes to LICENSE-3rdparty.csv, please
  run dd-rust-license-tool write and commit the changes. More details here.
• For new VRL functions, please also create a sibling PR in Vector to document the new function.

References

[pront]

Thanks, I agree that we should introduce this breaking change to fix the data loss scenario.

[tessneau]

makes sense to me, thanks for the changes 🙏 should we remove the bug label with the latest update?

[bruceg]

I'm still confused by the error type naming, but I will approve this to unblock further work.