feat!: add upgrade handler for initializing ICS epochs (backport #3079)

[mergify]

Description

Closes: #XXXX

Add the initial consumer validator sets for all consumer chains. This is needed by ICS epochs.

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Author Checklist

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please add links to any relevant follow up issues.

I have...

• Included the correct type prefix in the PR title
• Added ! to the type prefix if API, client, or state breaking change (i.e., requires minor or major version bump)
• Targeted the correct branch (see PR Targeting)
• Provided a link to the relevant issue or specification
• Followed the guidelines for building SDK modules
• Included the necessary unit and integration tests
• Added a changelog entry in .changelog (for details, see contributing guidelines)
• Included comments for documenting Go code
• Updated the relevant documentation or specification
• Reviewed "Files changed" and left comments if necessary
• Confirmed all CI checks have passed

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I have...

• confirmed the correct type prefix in the PR title
• confirmed ! in the type prefix if API or client breaking change
• confirmed all author checklist items have been addressed
• reviewed state machine logic
• reviewed API design and naming
• reviewed documentation is accurate
• reviewed tests and test coverage

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This is an automatic backport of pull request #3079 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of 5c5447c has failed:

On branch mergify/bp/release/v16.x/pr-3079
Your branch is up to date with 'origin/release/v16.x'.

You are currently cherry-picking commit 5c5447c.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   app/upgrades/v16/upgrades.go
	modified:   app/upgrades/v16/upgrades_test.go

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	added by them:   .changelog/v16.0.0/dependencies/3079-init-ics-epochs.md
	added by them:   .changelog/v16.0.0/features/3079-init-ics-epochs.md

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