feat: Return addresses and amounts of claimed rewards

[donosonaumczuk]

For distributing fees and rewards across different beneficiaries it is a requirement to know the assets and amounts claimed.

For the fees we already have getClaimableFees function which works well for the purpose. Howerver, for rewards we do not have such getter.

As a solution, I am suggesting this modification to get the assets and amounts of the claimed rewards.

[donosonaumczuk]

I am thinking it probably must be a new interface version and implementation, because even when it does not modify the claimRewards function selector, it modifies the expected return data, which might bring issues for people doing calls as IATokenVault(address).claimRewards(...)

I think the case that fails if when you use the new interface with old code, as it will expect return data that is not there. I need to check what happens with the opposite case (old interface call over new impl code), I think it might succeed and discard the return data. I can do a proper test after we agreed to introduce this change.

[donosonaumczuk]

Closing this because we agreed on an approach of calculating off-chain the assets and passing in the array of them at the time of splitting rewards.