Add unit tests for contract upgrades functions

Let's add unit tests for functions `deployProxy` and `upgradeProxy` - it should cover successful deployment and upgrade and also cases where the upgrade shouldn't happen. 

Examples in the repo that already implemented unit tests for these functions [here](https://github.com/keep-network/keep-core/blob/main/solidity/ecdsa/test/WalletRegistry.Upgrade.test.ts).