Fix Invoice Linking

While the invoice links to the related invoice it would be better to fully display the invoice (INV-18) instead of (INV-)

Thanks for the bug report we'll take a closer look

@athornfam2 Are you able to replicate this on the demo? I don't seem to be able to.

Hello. I have similar issue. Adding second ticket to existing invoice generate new invoice.

Not 100% what might be causing this. There is a load of old code on that modal, maybe this will help: itflow-org/itflow1082