allow users to claim rewards without unstaking

[itirabasso]

we need to allow users to claim rewards without unstaking their tokens

Currently, the unstakeAndClaim function requires users to unstake before claiming rewards.
This can be inconvenient for some users and it would be beneficial to provide more flexibility in the reward claiming process.

Additionally claiming without unstaking would save additional friction if the user wants to keep the stake in the aludel or even restake the rewards in the same tx!