fix: changed how claimed variable is set in staking-payouts

[Imod7]

Description

In staking-payouts endpoint, the claimed field is returning false even when rewards are actually claimed.

Testing

The claimed variable is set in this line of code where we check if the requested eraIndex is included in the claimedRewards vector. After testing, it shows that the includes function does not work as expected and does not return true when the eraIndex is included in the array. The reason might be related to types because I tried to use includes when changed the type of the eraIndex and it returned true. However this is still weird because if I check :

• validatorLedger.claimedRewards.toRawType() -> it returns 'Vec<u32>' and
• eraIndex.toRawType() -> it returns 'u32'
  so I would expect includes to work even if I do not change anything.

Proposed Solution

On the other hand, if we use the indexOf function it returns correctly the index where era is found in the array.
This works and we have to make sure to add the query param unclaimedOnly=false.

[TarikGul]

LGTM, great fix!