Accrued.rewardsAccrued can be zero

[Rubilmax]

Issue

https://github.com/morpho-org/morpho-aave-v3/blob/03cee70c50a8d0abf3c5eebdd416127fe8a54ea5/src/RewardsManager.sol#L355-357

Accrued event is emitted without regard to rewardsAccrued: sometimes, when claiming rewards for assets the user didn't supply/borrow for, Accrued events are emitted because the reward's asset index was updated, without the user's data being updated.

Recommendation

Split the Accrued event in 2:

• RewardIndexUpdated(asset, reward, newAssetIndex): emitted whenever the asset's index is updated in storage
• RewardAccrued(asset, reward, user, rewardsAccrued): emitted whenever a user's rewards was accrued

What I think we can learn

• The condition rewardDataUpdated || userDataUpdated is too broad: each condition corresponds to a storage update, and should thus be bound to independent events

[MerlinEgalite]

Inspired by Aave's code but agree this was a mistake.