Extend ActiveMatchingDbChecker to determine if HLA has been updated

[zabeen]

ActiveMatchingDbChecker determines that matching algorithm has caught up with donor updates by checking for search availability of provided donor codes.

If only HLA has been edited, then search availability will remain the same, and with current logic, the checker will return the donor info before the active db has actually caught up, which could cause assertion on expected donor info to fail.

Could extend the checker to include donor HLA so that it will keep checking until the HLA is the same (or it runs out of retries).