Mistaken field created in _nullStatus function of NDB_BVL_Instrument

[CamilleBeau]

Describe the bug
The function _nullStatus in NDB_BVL_Instrument class checks for fields ending with _status having set values, and sets their corresponding fields without _status to null. An array of data from flag often includes the field Data_entry_completion_status. When passing this array through _saveValues function to save, this results in a mistake where a new field Data_entry_completion is created and set to null.

A possible solution to this would be to move the Data_entry_completion_status field into its own column in the flag table.