CMIP6 MPI-ESM1-2-HR has a corrupt file in our store

Specifically, `tas_day_MPI-ESM1-2-HR_historical_r1i1p1f1_gn_19750101-19791231.nc` is 0 bytes.

For now, I've skipped making zarrs for `MPI-ESM1-2-HR` entirely. If we do in fact require the data from this model, we will need to deal with this missing data and then re-run `scripts/rechunk_to_zarr_cmip6.py`