Small fix to experiment_type schema
Small fix to experiment_type schema

4dn-dcic/fourfront,hms-dbmi/fourfront,hms-dbmi/fourfront,4dn-dcic/fourfront,hms-dbmi/fourfront,4dn-dcic/fourfront,hms-dbmi/fourfront,hms-dbmi/fourfront,4dn-dcic/fourfront