Use stacks block timestamp for block ingestion

[zone117x]

Stacks block timestamps have been added to Nakamoto blocks in stacks-network/stacks-core#4846

API code currently takes Date.now() during block ingestion for this value:

stacks-blockchain-api/src/event-stream/event-server.ts

Lines 251 to 258 in eada84e

	if (!blockData.block_time) {
	// TODO: if the core node can give use the stacks-block count/index for the current tenure/burn_block then we should
	// increment this by that value so that timestampts increase monotonically.
	const stacksBlockReceiptDate = db.isEventReplay
	? msg.burn_block_time
	: Math.round(Date.now() / 1000);
	blockData.block_time = stacksBlockReceiptDate;
	}

• Needs to be adjusted to use the value from the core node event
• Core node /new_block event may need modified to include this new value

[zone117x]

Confirmed this is working as expected with latest stacks-core develop 🎉