Add work around for missing columns that have already been dropped in an earlier stage, for method _filter_invalid_data

cdplib/db_migration/MigrationCleaning.py

@@ -234,7 +234,7 @@ class MigrationCleaning:
             columns = db.get_column_names(tablename=self._inconsist_report_table)
 
             if len(columns) > 0:
-                columns_not_in_data = [column for column in colunmns if column not in data.columns]
+                columns_not_in_data = [column for column in columns if column not in data.columns]
                 data_inconsist[columns_not_in_data] = 'Column does not exist in the mongo database and has therefore been dropped'
                 data_inconsist = data_inconsist[columns]