Update the logic for pruning the unfinalized headers

[nazarhussain]

Problem description

In @lodestar/prover we store the payloads and roots. The roots are divided into finalized and unfinalized categories. The finalized roots are cleaned based on MAX_PAYLOAD_HISTORY.

lodestar/packages/prover/src/proof_provider/payload_store.ts

Lines 177 to 181 in 08b82af

	for (
	let blockNumber = this.finalizedRoots.max - MAX_PAYLOAD_HISTORY;
	blockNumber > this.finalizedRoots.min;
	blockNumber--
	) {

There could be cases when chain is not finalized and endup huge memory bloat for unfinalized root.s

Solution description

We nee to develop similar limit for unfinalzied roots similar to MAX_PAYLOAD_HISTORY. And this value should be configureable so based on different networks user can configure.

Additional context

Extracted from #4706