Remove the data hash and square size from Data

[rach-id]

After implementing #1040, we should remove the unused data hash and square size from:

celestia-core/proto/tendermint/types/types.proto

Lines 84 to 104 in c3ab251

	// Data contains all the information needed for a consensus full node to
	// reconstruct an extended data square.
	message Data {
	// Txs that will be applied to state in block.Height + 1 because deferred execution.
	// This means that the block.AppHash of this block does not include these txs.
	// NOTE: not all txs here are valid. We're just agreeing on the order first.
	repeated bytes txs = 1;
	reserved 2, 3, 4;
	// field number 2 is reserved for intermediate state roots
	// field number 3 is reserved for evidence
	// field number 4 is reserved for blobs
	// SquareSize is the number of rows or columns in the original data square.
	uint64 square_size = 5;
	// Hash is the root of a binary Merkle tree where the leaves of the tree are
	// the row and column roots of an extended data square. Hash is often referred
	// to as the "data root".
	bytes hash = 6;
	}

The PR doing this should be targetting the main branch.

[evan-forbes]

are we still wanting to do this after our conversations in #1051?

[rach-id]

I am still looking at how it can be done, but I am not prioritizing it at the moment because it's post mainnet stuff.
I am fine if you prefer to close it for now