[EASY] Migrate cow_amm to alloy (#3879)

# Description
Migrates the rest of the cow_amm to alloy

# Changes
<!-- List of detailed changes (how the change is accomplished) -->

- [ ] Removes the ethcontract dep
- [ ] Replaces use on re-export

## How to test
Tests

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## Related Issues

Fixes #
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Author: jmg-duarte

Cargo.lock

@@ -10,7 +10,6 @@ app-data = { workspace = true }
 async-trait = { workspace = true }
 contracts = { workspace = true }
 database = { workspace = true }
-ethcontract = { workspace = true }
 ethrpc = { workspace = true }
 futures = { workspace = true }
 model = { workspace = true }

crates/cow-amm/Cargo.toml

@@ -1,8 +1,8 @@
 use {
     crate::{Amm, cache::Storage},
     contracts::alloy::ERC20,
-    ethcontract::futures::future::{join_all, select_ok},
     ethrpc::Web3,
+    futures::future::{join_all, select_ok},
     shared::maintenance::Maintaining,
     std::sync::Arc,
     tokio::sync::RwLock,