rcv: RC Entry of factura has blank emisor razón social

[sentry]

Can a RcRegistroDetalleEntry of a (non-electronic) factura (<RcvTipoDocto.FACTURA: 30>) have a blank (empty string) emisor razón social?

Sentry Issue: FD-CL-DATA-13E

ValueError: Value must not be empty.
  File "cl_sii/rcv/parse_csv.py", line 1175, in _parse_rcv_csv_file
    entry = input_csv_row_schema.to_detalle_entry(deserialized_row_data)
  File "cl_sii/rcv/parse_csv.py", line 784, in to_detalle_entry
    detalle_entry = RcRegistroDetalleEntry(
  File "<string>", line 12, in __init__
    from datetime import date, datetime
  File "cl_sii/rcv/data_models.py", line 281, in __post_init__
    cl_sii.dte.data_models.validate_contribuyente_razon_social(self.emisor_razon_social)
  File "cl_sii/dte/data_models.py", line 76, in validate_contribuyente_razon_social
    raise ValueError("Value must not be empty.")

Deserialized data to data model instance conversion failed (probably a programming error).

[glarrain]

CC @yaselc @yanosky

[yaselc]

CC: @ycouce-cdd