Fetching staker from stakerId is duplicated.

[ashish10677]

Rationale

Staker value is fetched in https://github.com/razor-network/razor-go/blob/33bdf45d066526da1eaa2ac4da8e7f92e5d2f7e2/cmd/vote.go#L154

But while calling HandleCommit it is again fetched, increasing the number of RPC call.
https://github.com/razor-network/razor-go/blob/33bdf45d066526da1eaa2ac4da8e7f92e5d2f7e2/cmd/vote.go#L279

This can be avoided if we pass staker instead of stakerId to the HandleCommit function.

Implementation

Pass staker instead of stakerId and modify the HandleCommit function accordingly.