Use `MAX_PAYLOAD_SIZE` in place of `GOSSIP_MAX_SIZE`

[michaelsproul]

Per this PR:

• Update Config Values to Match With the Latest Spec eth-clients/hoodi#5

The spec has moved from using GOSSIP_MAX_SIZE to MAX_PAYLOAD_SIZE.

While adding Hoodi in this PR (#7145) I opted just to continue using GOSSIP_MAX_SIZE. All these parameters have the default values currently, so it doesn't make any difference.

Eventually we should switch over to using MAX_PAYLOAD_SIZE and the new values. I don't think we need to worry about backwards-compatibility, because these params are relatively unimportant, and the only thing we will be breaking will be local testnet setups using old testnet dirs.

[pawanjay176]

I noticed this too and started a PR right before the holesky fork. It slipped my mind after with all the chaos, I'll revive this tomorrow.