enricher-aggregator fails if there are no findings

[linear[bot]]

The enricher-aggregator fails if there are no enriched findings, or in general, no findings. It shouldn't fail the whole pipeline.

It fails, because the previous enrichers had nothing to enrich, and as such, the enriched output file path doesn't exist:

https://github.com/ocurity/dracon/blob/ca533cd86b19648d372a727c7261e699c4e23dd6/pkg/putil/load.go#L98-L99

Desired Result

• Enrichers should always write results
• If there are no findings, an empty enriched results with 0 findings should be written
• Ensure we can somewhat enforce this, i.e. during development etc. a warning is raised if you don't always write
  • e.g. via a hook?
  • e.g. via a semgrep rule?
  • -> This will be tackled later, as part of an improved SDK
• Switch over all existing enrichers to follow this principle

Follow-Up

• [X] Go through all other stages (producers, source) and check they also always write something