The thing I have to ask is why is AVAST taking it upon itself to question what are very likely perfectly safe and legitimate add-ons seemingly based on little more than some arbitrary, high unreliable user reputation rating?
You get the same sort of thing with what AVAST decides to flag as a suspicious program when you go to download it. AVAST pops up a blocking, warning message saying this is an obscure, rarely downloaded piece of software you need protecting from. Its rarity is apparently the only criteria being used to suggest it must be have been written by demons intent on corrupting your PC's soul.
Although there is no specific ignore button in this case you can just cancel the message and continue. But why the annoying interference, which can sometimes occur after the download has started messing it up, simply because it is unusual and not, as you want, because it actually contains something malicious?