Deleting the correction on pCO2 observations included in MedBGCins

[vdibiagio]

Branch associata: https://github.com/inogs/bit.sea/blob/pco2_static_corr

pCO2_rec is the pCO2 in situ reconstructed in the MedBGCins dataset.

Since in the validation procedure we compare profiles of pCO2 from model and from MedBGCins (i.e., both in situ values), in this branch we deleted the correction we used on PCO2_rec:

if var == "pCO2_rec":
            Ptot= 1 + depth/10  # approximation for total pressure in atmosphere:
                                #! press atm + press water column (in atmosphere)
            values= values /  ( np.exp( ( 1-Ptot) *0.001366 ) )

(accounting for pressure effect) which is currently in the DatasetExtractor.py script in the main branch (lines 120-123):
https://github.com/inogs/bit.sea/blob/master/src/bitsea/static/DatasetExtractor.py

Note: deleting the correction will decrease pCO2 values of MedBGCins of about 3% at 200 m depth.

Moreover, after this correction, the reference climatology for pCO2 shoud be recreated via the script:
https://github.com/inogs/ogstm_preproc/blob/main/Climatologies/StaticDatasets/clim_for_medbgcins_archive.py