Fix for issue 4860 - Added in process_justification_and_finalization

[zack-scott]

Issue Addressed

This PR addresses the issue of compute_attestation_rewards_altair not taking into account the justified epochs attestation rewards when coming out of an inactivity leak.

Which issue # does this PR address?
#4860

Proposed Changes

Added in process_justification_and_finalization to the compute_attestation_rewards_altair function as suggested in issue.

Please list or describe the changes introduced by this PR.
The changes allow for calculation of attestation rewards when coming out of an inactivity leak.

Additional Info

Please provide any additional information. For example, future considerations
or information useful for reviewers.

[zack-scott]

@jimmygchen hey, I added in the logic process_justification_and_finalization for the compute_attestation_rewards_altair function, but I wasn't sure if we also needed to add in the process_justification_and_finalization to the phase0 logic compute_attestation_rewards_base as well?

[michaelsproul]

I wasn't sure if we also needed to add in the process_justification_and_finalization to the phase0 logic compute_attestation_rewards_base as well?

Good point. I think we do, as phase0 rewards calculation also uses is_in_inactivity_leak.

[zack-scott]

I wasn't sure if we also needed to add in the process_justification_and_finalization to the phase0 logic compute_attestation_rewards_base as well?

Good point. I think we do, as phase0 rewards calculation also uses is_in_inactivity_leak.

@michaelsproul sounds good, I will get the logic added for phase0 and tested as well

[zack-scott]

@michaelsproul I have added in the logic for phase0 to process the justification and finalization and added in tests to ensure it is working as expected.

[zack-scott]

@michaelsproul @jimmygchen this PR is ready for review

[jimmygchen]

Looks great! Thanks @zack-scott