fix: 🐛 try to ensure only one job can get the lock

As it's difficult to test on multiple MongoDB replicas (we should do it at one point), I'll try to:
- merge to main
- deploy on prod
- refresh the dataset severo/flores_101
- see if all the configs could be processed for the parquet creation, or if we still have an error for "half" of them

fix: 🐛 try to ensure only one job can get the lock: 
As it's difficult to test on multiple MongoDB replicas (we should do it at one point), I'll try to:
- merge to main
- deploy on prod
- refresh the dataset severo/flores_101
- see if all the configs could be processed for the parquet creation, or if we still have an error for "half" of them
