Transaction IDs for a contribution that are initially null are always null
This ticket is the result of the inquiry in this other #468 (closed)
"Normal behaviour"
- Create a contribution with transaction ID
- Visualize contribution, transaction ID is present
- Edit payment details and set a different transaction ID
- Visualize contribution, new transaction ID is appended to the old transaction ID
Buggy behaviour
- Create a contribution with transaction ID null
- Edit payment details and set a transaction ID value
- Visualize contribution, transaction ID isn't present