feat: allow reverting to preload if fallen behind

[Sekhmet]

This adds ability to revert to preload if sequential indexing ends up falling behind. We check latest block every 50 blocks and if if it's more than BLOCK_PRELOAD_OFFSET * 2 ahead of us preload will be activated again.

Test plan

1. Run with SX API.
2. Change ARB1 start block to 312004031.
3. Run it as ENABLED_NETWORKS=arb1 yarn dev.
4. You will see it starts with preload, then it switches to sequential indexing.
5. After a while latest block check fires and you get info how behind we are.
6. If we are more than 100 blocks behind you will see message we are reverting to preload.
7. Preloading happens.
8. Now we are going sequential as well with less than 100 blocks behind.

PR Overview

This PR implements a fallback mechanism that reverts the indexing mode to preload when the sequential indexing falls significantly behind.

• Introduces a constant (CHECK_LATEST_BLOCK_INTERVAL) to trigger periodic latest block checks.
• Adds logic to compare the current block number with the latest block number and update the preload range when lag exceeds the threshold.
• Includes minor logging adjustments in the preload section.

Reviewed Changes

File	Description
src/container.ts	Adds logic to trigger a revert to preload indexing when too far behind

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Comments suppressed due to low confidence (2)

src/container.ts:250

• Ensure that the variables 'checkpointBlock' and 'preloadedBlock' are correctly defined and updated prior to this condition. It is critical to verify that the intended fallback behavior is triggered only when appropriate values are available.

if (!checkpointBlock && !preloadedBlock) {

src/container.ts:262

• Double-check that resetting 'this.preloadEndBlock' with 'latestBlock - BLOCK_PRELOAD_OFFSET' aligns with the overall block handling strategy without inadvertently skipping blocks or disrupting the intended preload range.

this.preloadEndBlock = latestBlock - BLOCK_PRELOAD_OFFSET;