[EVM] Expand unit tests

[Thaleszh]

Is your feature request related to a problem? Please describe.
The current tests are only covering the IBC precompile and a simple wallet connection. Expanding tests is needed to make sure the library is behaving as expected in the future.

Describe the solution you'd like
Test a new EVM precompile by:

1. Creating a respective file on packages/evm/tests on a file named precompileName.test.js. The jest should already be in place for the test to be executed.
2. Adding unit tests to it
3. Making sure they can run on the pipeline

Improvement to the utils or existent tests are also welcomed.

Additional content
Don't forget to set up an env variable with a wallet key and with testnet funds, you can obtain funds from the faucet. You can then utilize the utils to set up a wallet connection.

The README.md contains the list of methods of each of the precompiles, as well as their signature.

[isonnymichael]

Hi @Thaleszh, since the package export still has several issues, I’d like to focus on working on this first.