Fix retether duplicates

Retether with Canon R5 causes duplicates of all images in Capture One.

It turns out the C1 copies all files from both camera cards, even though the files will have the same original camera file name, hence the duplication. C1 should check for duplicates similar to the import - Exclude Duplicates.

See fault report 268962

Based on the internal analysis and multiple tests peformed by the engineering team, this issue can pop up due to several memory cards with images being used during tethering. Capture One ReTether will read the files from both of them leading to the duplicates you see in the Session.

Please update the software to the latest version (16.6.3) and make sure you have only one SD card in use. That should help to solve the problem.

I should be allowed to maintain a backup on both cards in the camera.