You only need transit visas if you will be passing through immigration, sometimes you have to, such as when you need to change airports. You have minimal layover time at Dublin airport and I think you are not even changing terminal, in that case no need for any kind of visa.
Also, a word of advise, it seems a code-share flight, so look out when you are searching for your gate at the airport, means it's totally possible that you are assuming it's an AA flight but Etihad is carrying you or vice versa, in this case they will be showing flight numbers of both airlines, both will be different, just keep a good eye on them!