fix duplicated protocols error when same scan type returned (#856)

Author: cmadjar

python/lib/imaging.py

@@ -669,7 +669,7 @@ def look_for_matching_protocols(self, protocols_list, scan_param):
             elif self.is_scan_protocol_matching_db_protocol(protocol, scan_param):
                 matching_protocols_list.append(protocol['Scan_type'])
 
-        return matching_protocols_list
+        return list(dict.fromkeys(matching_protocols_list))
 
     def is_scan_protocol_matching_db_protocol(self, db_prot, scan_param):
         """