The function returns a TEXT representing the name of the active user playing a project role with the name projectRoleName in the current issue's project, and has the lower number of issues with resolution empty assigned; or ""
if there isn't any user in the project role.
Parameter projectRoleName can be a comma-separated list of project role names, returning the least busy users among the project roles.
leastBusyUserInRole(text projectRoleName) #Output: Text