Is your feature request related to a problem? Please describe.
If some samples have only unclassified reads, passing the artifact to estimate-bracken action results in an error "Error: no reads found. Please check your Kraken report".

Describe the solution you'd like
It would be useful to have an action similar to filter-contigs or filter-mags which will allow filtering reports based on criteria but also simply removal of samples without any classification results.

Additional context
For the linked QIIME 2 Forum discussion see here.