Tickets/DM-26554: Use decam ISR configs for bias and flat construction

[isullivan]

The config settings set in config/isr.py were used correctly in processCcd.py, but were not used for constructBias.py or constructFlat.py. This was not a problem for processing that used the Decam community pipeline calibrations, but resulted in the incorrect processing of the master bias in particular.

The defaults in config/isr.py also turn on and apply settings that are incorrect for constructing the master bias or flat, so I explicitly disabled these in a separate commit.

[czwa]

Should the dark.py and fringe.py config files be updated as well? I see that regular DECam processing doesn't use a dark, but it still may be helpful to keep them up-to-date.