fix: More robust joining of surveys databases

Handle missing redundant columns and continue to set a common column
order at the same time.

coordinator/ProcessorSurveys.py

@@ -152,7 +152,8 @@ def process_in_job_survey(jobPath,status,config,component):
             continue
 
         # re-order columns to match first case (presumed standard format)
-        dfi = dfi[standard_columns]
+        # and fill missing columns with empty strings
+        dfi = dfi.reindex(standard_columns,fill_value='',axis='columns')
 
         logger.debug(f"Next processed form contains {dfi.shape[0]} records")