chore: increase LOOK_BACK_BLOCK_RANGE to 2.5 mil (#4549)

## What ❔

Increase LOOK_BACK_BLOCK_RANGE to 2_500_000

## Why ❔

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## Is this a breaking change?
- [ ] Yes
- [ ] No

## Operational changes
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Author: dimazhornyk

core/node/eth_watch/src/client.rs

@@ -87,7 +87,7 @@ pub trait EthClient: 'static + fmt::Debug + Send + Sync {
 }
 
 // This constant is used for reading auxiliary events
-const LOOK_BACK_BLOCK_RANGE: u64 = 1_000_000;
+const LOOK_BACK_BLOCK_RANGE: u64 = 2_500_000;
 pub const RETRY_LIMIT: usize = 5;
 const TOO_MANY_RESULTS_INFURA: &str = "query returned more than";
 const TOO_MANY_RESULTS_ALCHEMY: &str = "response size exceeded";