dailyops pipeline crash on zero-sized test file

20231226/0021376/desi-00213760.fits.fz is a bogus zero-sized FITS file that the desiops pipeline crashed on. At the same time, it was a test exposure with a valid request file that we could have parsed to know to skip it:

  “SEQUENCE”: “Spectrographs”,
  “FLAVOR”: “zero”,
  “OBSTYPE”: “other”,
  “NOADJUSTMENTS”: true,

@akremin in the pipeline refactor, let's test this case and immediately skip over the exposure if the request*.json file is OBSTYPE=other. If there is an actual use case for needing to read the raw data file even for test exposures, please describe that here and we'll sort out a way to be more robust to this.

Current failure from ~desi/daily/logfiles/daily-20231226.log

##################### 213760 #########################
INFO:exptable.py:437:summarize_exposure: Summarizing exposure: 213760
INFO:exptable.py:451:summarize_exposure: Using user specified colnames and coldefaults.
INFO:exptable.py:505:summarize_exposure: Found request file: /global/cfs/cdirs/desi/spectro/data/20231226/00213760/request-00213760.json
INFO:exptable.py:549:summarize_exposure: Found raw data file: /global/cfs/cdirs/desi/spectro/data/20231226/00213760/desi-00213760.fits.fz
Traceback (most recent call last):
  File "/global/common/software/desi/perlmutter/desiconda/20230111-2.1.0/code/desispec/main/bin/desi_daily_proc_manager", line 165, in <module>
    daily_processing_manager(specprod=args.specprod, exp_table_path=args.exp_table_path,
  File "/global/common/software/desi/perlmutter/desiconda/20230111-2.1.0/code/desispec/main/py/desispec/scripts/daily_processing.py", line 261, in daily_processing_manager
    erow = summarize_exposure(path_to_data, night, exp, expobstypes, colnames, coldefaults, verbosely=False)
  File "/global/common/software/desi/perlmutter/desiconda/20230111-2.1.0/code/desispec/main/py/desispec/workflow/exptable.py", line 550, in summarize_exposure
    dat_header, fx = load_raw_data_header(pathname=datpath, return_filehandle=True)
  File "/global/common/software/desi/perlmutter/desiconda/20230111-2.1.0/code/desispec/main/py/desispec/workflow/desi_proc_funcs.py", line 211, in load_raw_data_header
    fx = fitsio.FITS(pathname)
  File "/global/common/software/desi/perlmutter/desiconda/20230111-2.1.0/conda/lib/python3.10/site-packages/fitsio/fitslib.py", line 520, in __init__
    self._FITS = _fitsio_wrap.FITS(filename, self.intmode, create)
OSError: FITSIO status = 107: tried to move past end of file
ffopen could not interpret primary array header of file: 
/global/cfs/cdirs/desi/spectro/data/20231226/00213760/desi-00213760.fits.fz

Start in py/desispec/workflow/exptable.py at summarize_exposure, and trace how the request*.json file is parsed before the raw data header is loaded through load_raw_data_header in desi_proc_funcs.py. Reproduce the zero-sized FITS case from the daily log and verify that an exposure whose request has OBSTYPE="other" is skipped without attempting to open the raw data file.