fix: avoid import conflicts between v4-sdk and ethers-v6

[Amxx]

Description

v4-sdk uses ethers v5, which is slowly going away. Many project that import v4-sdk may also have ethers-v6 in their dependency. This creates conflicts, because v4-sdk imports ethers directly (instead of importing @ethersproject/xxx).

How Has This Been Tested?

This is only a change to the imports. There should be no feature changes. Was tested with yarn test

Are there any breaking changes?

There shouldn't be any.

Feedback Focus

The dependencies of the v4-sdk package do not include ethers. It only contains @ethersproject/solidity. However, v4-sdk does use features from all of the following

@ethersproject/abi
@ethersproject/address
@ethersproject/bignumber
@ethersproject/constants
@ethersproject/hash
@ethersproject/solidity
@ethersproject/units
@ethersproject/abstract-signer

Maybe they should be added to the dependencies in a more explicit way

Follow Ups

Migration to ethers v6: #141

[jsy1218]

I will give a test to smart order router and routing-api on my local to make sure this PR is good

[jsy1218]

I'm hitting weird issue on my local https://app.warp.dev/block/QhX8rzl8rm2lPoL2m7ysSQ. Although peeking this PR, I don't think it's causing the weird issue.

[Amxx]

Vscode did some linting changes automatically. I just reverted them.