staking: add missing effect for Defined <> Inactive

[erwanor]

There is a bug in the current v0.65.0 release. Defined validators are not transitioning out of the precursor state into Inactive. The reason is that we are not actually effecting the validator state. This had been previously fixed in a follow-up #2921, but somehow slipped back in.

[hdevalence]

Great find, unfortunate bug. Since this would change the execution of previous blocks, I'm not sure we can easily merge this without causing newly syncing nodes to diverge. I suspect the best course of action here (cc @conorsch) is:

• Merge, rewrite the git tag, nuke the existing network and redeploy (it's only a day old, we've done no big announcements, etc).
• Discuss in a retro of how we could (a) mitigate root causes leading to the bug and (b) how we could make remediation less painful if we were to experience a similar bug in the future.

I think this will be a useful learning experience.

[conorsch]

Merge, rewrite the git tag, nuke the existing network and redeploy

Slight change after discussion: we'll push up a fresh tag, to avoid breaking repos in the wild, v0.66.0. Then we'll indeed fully deploy, nuking all chain state and resetting to 0. We'll still use the same chain id, so the name "Deimos" still refers to the batch of changes we tried to ship yesterday.

[conorsch]

Post-merge, I will deploy an ad-hoc validator on preview and confirm it can reach the active set.