scaling: fix state store corruption bug for job scaling events #23673
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When updating a `JobScalingEvent`, the state store function did not copy the existing object before mutating it. This corrupts the state store because it modifies the leaf node without committing it in a transaction. It can also cause the Nomad server to crash with a "fatal error: concurrent map read and map write" if its `ScalingEvents` map is read via the `ScaleStatus` RPC at the same time as it's being written. This changeset also removes some mostly-unused public methods on the struct that dangerously encourage you to mutate it outside of a copy. Ref: https://hashicorp.atlassian.net/browse/NET-10529
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schmichael
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jrasell
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When updating a
JobScalingEvent, the state store function did not copy the existing object before mutating it. This corrupts the state store because it modifies the leaf node without committing it in a transaction. It can also cause the Nomad server to crash with a "fatal error: concurrent map read and map write" if itsScalingEventsmap is read via theScaleStatusRPC at the same time as it's being written.This changeset also removes some mostly-unused public methods on the struct that dangerously encourage you to mutate it outside of a copy.
Ref: https://hashicorp.atlassian.net/browse/NET-10529