fix: run 10x less events in `clas12-validation` high-stats tests

Created by: c-dilks

Now that we have the full matrix of ( event generation types, configurations ) validation tests, it turns out that 10k events is too time consuming.

The validation dispatch from the most recent PR merge to development was auto-cancelled since the job time exceeded GitHub's limits: https://github.com/JeffersonLab/clas12-validation/actions/runs/6561980932

So for now, let's run 1k events in the high-stats test.