Fix issue with short index for IOVPayload PT conversion
This applies the same fix to Database/IOVDbPTCnv/ IOVPayloadContainerPTCnv_p1
as it was already done for Database/IOVDbTPCnv/ IOVPayloadContainerCnv_p1 in !37346 (merged)
The related Jira ticket is ATR-22116
This should go into all releases.