Sanity check on the VFAT config DB dump

Description

When the vfat information about the IREF and VREF are gotten from the DB there should be a sanity check that prevents duplicate values. Unfortunately in the DB there could be more "run numbers" associated with the desired DAC:

SQL> SELECT vfat3_barcode, iref, RUN_NUMBER FROM CMS_GEM_MUON_VIEW.GEM_VFAT3_PROD_SUMMARY_V_RH WHERE vfat3_ser_num = '0x2570';

VFAT3_BARCODE                       IREF RUN_NUMBER
---------------------------------------- ---------- ----------
3063000110001709584                 31        91
3063000110001709584                 31        86
3063000110001709584                 31        91

This can create warnings downstream.