Update Swap Modal to inform users of refund ETH

When a user wants to purchase more $AGENT tokens than currently allowed, they will get a refund - this UX optimisation was implemented to the smart contract so that users could just max purchase $AGENT when its about to reach 100% bonding.

We need to inform users in the swapping modal of this feature so that they are aware of this before continuing to purchase.

For UI guidance, we should use the "Information Dialog” under the “transaction details” box.