Request JSONs need to be pre-processed to prefix bytes with leading `0x` if not present

With chia-blockchain moving to chia_rs, bytes values parsed from JSON are now enforced to have a leading 0x: https://github.com/Chia-Network/chia_rs/blob/main/crates/chia-protocol/src/bytes.rs#L97-L101. According to https://github.com/Chia-Network/chia-blockchain/issues/13623, this enforcement is the expected and desired behaviour.

The Chia Pool Protocol 1.0 specification, however, allows bytes to be sent without leading 0x: "All bytes values are encoded as hex with optional 0x in front" (https://github.com/Chia-Network/pool-reference/blob/main/SPECIFICATION.md#https-endpoints-summary).

There are farmer implementations in the wild which send some values without a 0x prefix.

Thus, parsing of all JSON request payloads (PostFarmerRequest, PutFarmerRequest, and PostPartialRequest) needs to be adjusted to pre-process the JSON payload and prepend 0x in bytes field where the 0x is not present.

Locate the JSON parsing entry points for PostFarmerRequest, PutFarmerRequest, and PostPartialRequest, then read how their bytes fields are currently decoded. Pre-process each request payload so bytes without a leading 0x are accepted while existing prefixes remain valid; done means all three request types handle both forms consistently.