AVG_L1_BLOCK_TIME is incorrect / misleading

[sambacha]

AVG_L1_BLOCK_TIME

We see it defined here: https://github.com/Uniswap/interface/blob/809841df0a8fbeb98bde1780081f1170c84aa283/src/constants/chainInfo.ts#L24

Officially, L1 block time is defined here: https://github.com/ethereum/consensus-specs/blob/dev/specs/phase0/beacon-chain.md#time-parameters-1

Furthermore, an average of 12 would be lower than any observed block times post muir-glacier in a pre-PoS setting to begin with.

Probably not a big deal, just thought to mention it.