Leading zeros on Quantity values are not trimmed.

[gakonst]

Problem

See the Foundry issue for motivation & proposed solution: foundry-rs/foundry#1590

[mattsse]

this happens in

ethers-rs/ethers-providers/src/lib.rs

Line 471 in 916e9a7

location: H256,

due to the H256 which formats padded

ethers-rs/ethers-providers/src/provider.rs

Line 734 in 916e9a7

let value: String = self.request("eth_getStorageAt", [from, location, block]).await?;

but the location in eth_storage_at is a Quantity number according to the spec, I guess we can simply convert it to a U256 first?