fix category filtering in api
fix category filtering in api

tndatacommons/tndata_backend,izzyalonso/tndata_backend,tndatacommons/tndata_backend,izzyalonso/tndata_backend,tndatacommons/tndata_backend,tndatacommons/tndata_backend,izzyalonso/tndata_backend,izzyalonso/tndata_backend