gethclient: preserve requireCanonical in BlockReceipts

[Bilogweb3]

We kept ethclient.BlockReceipts aligned with execution-apis by reverting it to pass BlockNumberOrHash.String(), then implemented the requireCanonical-preserving path in gethclient.BlockReceipts where the flag is actually supported, and added an in-proc test in the gethclient package to prove the flag survives the roundtrip.

[rjl493456442]

https://github.com/ethereum/execution-apis/blob/f910189261255eb0ebc49ee0e6f10f48562a41c3/src/eth/block.yaml#L221

According to the ethereum execution-apis spec, it doesn't say requireCanonical is the spec'd field. It's probably just a geth-related RPC argument.

As the ethclient is cross-client SDK and shouldn't be bound with Geth implementation.

If you really want to integrate the requireCanonical into ethclient, we need to change the execution-apis spec first.

[Bilogweb3]

@rjl493456442 thanks for pointing this out. I reverted ethclient.BlockReceipts to the spec-compliant string argument so the cross-client SDK no longer depends on geth-only flags. The requireCanonical - preserving call now lives in ethclient/gethclient.BlockReceipts (where those flags are supported) and I added a small in-proc test to prove the flag survives the roundtrip. Once execution-apis incorporates requireCanonical we can move this back into ethclient.

Title and description updated accordingly.