[BlackboxBenchmarking] Remove dry run arg from aggregate_fuzzer_stats cron

[dylanjew]

removes dry run args and makes args optional in aggregate_fuzzer_stats cron job

The bot version of run_cron.py does not accept any args, while the local run_cron.py does accept args.

I previously used required args and this caused the cron job to fail in dev after I pushed the helm config.

Unhandled exception in cron: main() missing 1 required positional argument: 'argv'
Traceback (most recent call last):
  File "/mnt/scratch0/clusterfuzz/src/python/bot/startup/run_cron.py", line 68, in main
    return 0 if task_module.main() else 1
                ^^^^^^^^^^^^^^^^^^
TypeError: main() missing 1 required positional argument: 'argv'

[ViniciustCosta]

Yeah, the local run_cron.py is different from the prod one. I think this was a recent change unfortunatelly.