Award one credit per dequeued vote when processing VoteStateUpdate in… (backport #25743)

[mergify]

This is an automatic backport of pull request #25743 done by Mergify.
Cherry-pick of cbb0f07 has failed:

On branch mergify/bp/v1.10/pr-25743
Your branch is up to date with 'origin/v1.10'.

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Changes to be committed:
	modified:   program-test/src/lib.rs
	modified:   programs/stake/src/stake_state.rs
	modified:   programs/vote/src/vote_processor.rs
	modified:   programs/vote/src/vote_state/mod.rs

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   programs/stake/src/stake_instruction.rs
	both modified:   sdk/src/feature_set.rs

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/github/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

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[mergify]

automerge label removed due to a CI failure

[mvines]

Do we really want to backport this? Better to let it soak on testnet through the 1.11 stabilization cycle

[AshwinSekar]

sounds good

[bji]

Do we really want to backport this? Better to let it soak on testnet through the 1.11 stabilization cycle

In my opinion you cannot enable the VoteStateUpdate feature on mainline without this feature also. Because you'll be altering the way vote credits are awarded if VoteStateUpdate is enabled without this change.

If you're OK with not turning on VoteStateUpdate until at least 1.11, then it would be fine to not backport to 1.10.

[mvines]

VoteStateUpdate certainly cannot be enabled on mainnet without this feature