Fix receive blind block

[terencechain]

An attempt to fix #12103 by adding a payload cache to allow unblind beacon block when using a local execution client. Summary of how this weeks

• New cache where the key is payload hash and value is the beacon block
• When calling the ProduceBlindedBlock endpoint, if the local block (higher value) is used. We return the local blind block and cache the entire block
• When calling SubmitBlindedCapellaBlock, we first check if a cache entry exists before unblinding the block through the relayer. Skip builder path and return full local block if cache entry exists