Problem: `usecase/syncstrategy/window.go` one failure API request fails all API requests

@allthatjazzleo Reported that sometimes, our explorer is lagging behind.

Sometimes, some of our internal nodes lagged behind (block data source for indexing server). Then the indexing server failed to pull the latest blocks, and it caused the information on explorer was not the latest.

At the same time, some users were directed to explorer to check their transactions status (maybe through Defi wallet), and they can't find their transactions there, which was expected as the indexing server lagged behind.

## Problem

When we use `Window` `SyncStrategy`, (`usecase/syncstrategy/window.go`), we will pull block data in a batch manner.

However, if any of the blockchain nodes we are requesting are lagged behind, the pulling will be stuck.

Imagine we have three blockchain nodes behind the load-balancer.
- Node-1 is good, API request always return 200.
- Node-2 is lagged behind, API request to it will return 5XX error.

Say the Window size is 3. Then the indexing in one round will try to fetch 3 blocks.

It is possible some requests are directed to the lagging blockchain node, and it return 5XX error.

- Request-to-block-0: sent to Node-1, 200
- Request-to-block-1: sent to Node-2, 5XX
- Request-to-block-2: sent to Node-1, 200

Although block-0 and block-2 data is fetched, the `Window` will ignore them and return an error.

In our current setting, we have 3 blockchain nodes, and the window size is 50. Therefore, when one blockchain node is down or lag behind, it is very likely the pulling of block data will be blocked. As it is very likely one request among the 50 requests will sent to the lagged node, which blocks the projection.

Sometimes it could take a few minutes for the nodes to come back. During that time, users will be unable to access the latest tx data through our explorer. Their transactions may even be shown as 404.

## Proposal

Maybe we could change the implementation in `usecase/syncstrategy/window.go`.

Still in the above example, if block-1 is failed to retrieve, then we only return the block-0.

If we have 50 requests and the block-10 request failed, then we will return the block-0 ~ block-9 data.