Improve how technique search works for hierarchical entities

[CodyCBakerPhD]

Discovered during meeting on 8/31

Search based on technique needs some improvement

Example: https://dandiarchive.org/dandiset/search?search=technique:%22patch+clamp%22

does not find https://dandiarchive.org/dandiset/000228?search=patch-seq&pos=1 or any other

Problem: the 'patch clamp' key should not just look for PatchClampSeries but any child neurodata type such as VoltageClampSeries, CurrentClampSeries, etc.