jmespath: removing higher-level objects based on lower-level matches

[colleenXu]

I described some queries in #324 that were causing 500 errors.

But even if they worked, they wouldn't necessarily do what I had hoped

• first example: remove a chembl.drug_mechanism object in a document if its target_components.uniprot field (array? string if only 1 element?) didn't match the value specified
• second example: remove a civic.evidence_items object in a document if its disease.doid field (array? string if only 1 element?) didn't match the value specified

Chunlei may have previously said that this was doable.

[colleenXu]

Try using jmespath_exclude_empty.