Added test scenarios for delegation

[viktor-voitenko]

…ter delegation and vote cast

[jjranalli]

• about testCastVoteAfterDelegationAuthorities2, except the allowance check those assertions are verified on every castVote via castVoteBatchedAssertions. I suggest adding the allowance check in castVoteBatchedAssertions and removing the test altogether since it doesn't seem to add anything to existing tests.
• same is valid for testChangeDelegatorBalanceAfterCastVote which unless doesn't add anything to existing tests so can be safely removed
• minor note: forge formatting seems to not be working on file save. make sure to have NomicFoundation.hardhat-solidity VSCode extension installed for the moment to keep it consistent

@viktor-voitenko To proceed I suggest going through the test cases mentioned on notion, and implementing them in the repo if not already present