fix: forgot to implement Acquisition.instrument_id merge#1720

dbirman merged 3 commits intodevAllenNeuralDynamics/aind-data-schema:devfrom

1713-acquisition-merge-__add__-needs-to-merge-instrument_id-fieldsAllenNeuralDynamics/aind-data-schema:1713-acquisition-merge-__add__-needs-to-merge-instrument_id-fieldsCopy head branch name to clipboard