Implementation of eth_get_transaction_count function

[Gerson2102]

This PR include changes on the following file crates/contracts/src/kakarot_core/eth_rpc.cairo. I'm doing the implementation of the eth_get_transaction_count function. The issue is not done yet.

Pull Request type

Normal

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• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no API changes)
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Resolves: #942

Does this introduce a breaking change?

• Yes
• No

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This change is 

[Gerson2102]

I was checking in the codebase for more places where we can now use the eth_get_transaction_count but I didn't find any to be honest. Let me know if there is any that is missing. @enitrat

[Gerson2102]

I added one test. But I was thinking about change the nonce and check it again. But I dont really know how to do it... Maybe using set_nonce()?

[enitrat]

1. don't deploy contracts with setup_contracts_for_testing, just do a local, internal test with
   https://github.com/kkrt-labs/kakarot-ssj/pull/983/files#diff-843e16e046c7baf8fcae8e8d2c2bfc5f8aecfed6d81af61768352c08e6ac83f7R231

2. you can use mock_call from starknet foundry to mock the account call to get_nonce to return an arbitrary value - you can check existing usages in the codebase

[Gerson2102]

This is the test that I'm doing now:

#[test]
    fn test_eth_get_transaction_count() {
        let kakarot_state = set_up();
        // Deployed eoa should return a zero nonce
        let starknet_address = compute_starknet_address(
            test_address(), evm_address(), uninitialized_account()
        );
        start_mock_call::<u256>(starknet_address, selector!("get_nonce"), 0);
        assert_eq!(kakarot_state.eth_get_transaction_count(evm_address()), 0);
    }

And I'm getting this error:

[FAIL] contracts::kakarot_core::eth_rpc::tests::test_eth_get_transaction_count

Failure data:
    "Contract not deployed at address: 0x0"

That was the reason that I was using deploy_eoa() function before.

[enitrat]

the issue was that the setup function does not intitialize anyu storage var, thus the class used for address computation was 0