Problem

With the addition of chained merkle shreds, there is a new class of duplicate proofs available to be gossiped

Summary of Changes

Add a check for chained merkle root conflict proofs:

• Different fec set
• Lower fec set shred must be a coding shred
• Fec sets are adjacent
• Merkle root of the lower fec set must not equal the chained merkle root of the higher fec set

Fixes solana-labs#34897