[PDR-364] Get cohort value from old participant summary table. (#2543)
[PDR-364] Get cohort value from old participant summary table. (#2543)

* Get cohort value from old participant summary table.

* Move cohort look code to prep paricipant block.
all-of-us/raw-data-repository,all-of-us/raw-data-repository,all-of-us/raw-data-repository