temp fix for lumi report on workloadsummary

temp fix for #5216 
Hi Alan, Julian, Looking at the code again, making  run.lumis to set here set(run.lumis) won't help much here unless that is done the outside the 'for' block since converting to set will take O(n). So was that what you meant?
In that case we probably need to handle it in db query first. However, I would do it separately if this need to be deployed soon. If this still take too much time, I think we can reduce number len(run.lumis) > 10000 further down.
What do you think?