erp5_core: fix fullInventory case

check only date of Inventory in this case
3 jobs for skd in 0 seconds
Status Job ID Name Coverage
  External
failed P-PSA.UnitTest-SKD.PCPA

02:05:37

passed P-PSA.UnitTest-SKD.PCPA

02:54:59

passed P-PSA.UnitTest-SKD.PCPA

03:52:08