Allow multiple fields in filter search

The filter search should allow multiple filters, similar to the expand neighbor options.

## Filter search

## Expand neighbor

Start by locating the filter search implementation and the expand neighbor options shown in the issue screenshots, then compare how each accepts fields. Done means filter search supports multiple filters in a way consistent with expand neighbor options; add or update the relevant tests if the existing implementation has coverage.

Written by the indexing model from the issue text.