Minimize columns used by altMTL

Notes from the CAI call on 2025-01-16:

Full fiberassign calls inflate_ledger to get additional targeting columns like fluxes to propagate to the offline pipeline, but these aren't needed for the altMTL process. Investigate the minimal required set of columns and whether those can be achieved using just the MTLs without needing inflate_ledger.

From @araichoor in zoom chat:
```
For what is worth, I tried a call with fba_run with only those 18 columns, and it seems to run:
"TARGETID", "RA", "DEC", "REF_EPOCH", "PARALLAX", "PMRA", "PMDEC", "DESI_TARGET",
"BGS_TARGET", "MWS_TARGET", "SUBPRIORITY", "OBSCONDITIONS", "PRIORITY_INIT",
"NUMOBS_INIT", "SCND_TARGET", "NUMOBS_MORE", "NUMOBS", "PRIORITY”;
it s very likely that those are in the ledgers.
```

To which @geordie666 replied
```
Yep, those 18 columns are all in the ledgers already!
```

@LNapolitano @ashleyjross heads up