Describe the bug
The "Known contract address" is shown sometimes in the Send flow when sending tokens to a non-contract address. Specifically it seems to happen whenever you send to an external address (i.e. an address not in your wallet), and then switch to a token on the Send screen.

Steps to reproduce (REQUIRED)

1. Click 'Send' on the Home screen
2. Enter some external address (one that is not a contract address)
3. Select a token in the "Asset" dropdown
4. See the "Known contract address" warning

Expected behavior
The "Known contract address" warning should only be shown when the recipient of the send or token send is a known contract address.

Browser details (please complete the following information):

• OS: Linux
• Browser: Chrome and Firefox
• MetaMask Version: v8.1.8