[IMPLEMENTED] Do not update instantly an asset. Show a confirmation dialog

One of our contributors dragged a new image to create a new asset, but dropped it in the middle of the screen, updating another asset.
As there is no way to undo that operation, we got worried.
I would suggest to not update instantly but to show a confirmation dialog “Do you want to update the asset?”.

Makes sense, thank you

I have implemented that, will be deployed soon.