Handle swaps where user pays gas

[dcposch]

Summary

The following transaction should be a single TransferClog: 0xd812...

Instead, we see duplicate transfers:

Investigation

The transaction above produces a lot of transfers, including the following four :

• 0x4D35... sends $0.04 USDC to the PimlicoERC20Paymaster to pay gas limit
• 0x4D35... sends 210 DEGEN to Uniswap
• 0x4D35... receives $1.60 USDC from Uniswap
• 0x4D35... receives $0.02 USDC gas refund rom PimlicoERC20Paymaster

... the extra receives are causing duplicate transfer logs.

Proposed solution

Stopgap: filter our PimlicoERC20Paymaster transfer.
Better: gas accounting as part of Clog spec.