[Drain Account] Enhance transaction summary decoding

[JagoFigueroa]

Description

On Drain review screen:

1. specify that the address we are sending the funds to is a smart contract address when more than one asset is drained. A drain is a critical operation so seeing an address different to the one specified recipient itself can be scary for users.

2. Change the Send 0 eth to into something more generic, like send all/selected assets to:

[mmv08]

this should be a part of https://github.com/gnosis/safe-react-apps

[JagoFigueroa]

Removing a couple of enhancements from the list as yago already did some enhancements in pr https://github.com/gnosis/safe-react-apps/pull/173 + adding a new possible one :)