refactor(x/slashing): migrate AddrPubkeyRelation to collections

[likhita-809]

Description

Closes: #16364

---

Author Checklist

All items are required. Please add a note to the item if the item is not applicable and
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 or client breaking change
• targeted the correct branch (see PR Targeting)
• provided a link to the relevant issue or specification
• followed the guidelines for building modules
• included the necessary unit and integration tests
• added a changelog entry to CHANGELOG.md
• 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

Reviewers Checklist

All items are required. Please add a note if the item is not applicable and please add
your handle next to the items reviewed if you only reviewed selected items.

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
• manually tested (if applicable)

[julienrbrt]

Curious, why cannot you keep AddrPubkeyRelationKey function? It seems that the logic is still the same, just the prefix changes. Now you are duplicating the logic everywhere.

[likhita-809]

Curious, why cannot you keep AddrPubkeyRelationKey function? It seems that the logic is still the same, just the prefix changes. Now you are duplicating the logic everywhere.

Sorry for the confusion. This was not ready yet when you reviewed and I accidentally made it r4r. This got resolved in the later commits.

[facundomedica]

LGTM, can we remove AddPubkey and GetPubkey? They don't seem necessary anymore, also the diff test is passing

func (s *KeeperTestSuite) TestDiffCollsMigration() {
	s.SetupTest()

	pks := simtestutil.CreateTestPubKeys(100)
	err := sdktestutil.DiffCollectionsMigration(
		s.ctx,
		s.key,
		100,
		func(i int64) {
			s.slashingKeeper.AddPubkey(s.ctx, pks[i])
		},
		"f637ced4115e154632912552c6974d5ec8ffcb013ac446e91b0fb2d76f669d87",
	)

	s.Require().NoError(err)
}

[likhita-809]

LGTM, can we remove AddPubkey and GetPubkey? They don't seem necessary anymore, also the diff test is passing

we can remove AddPubkey. But GetPubkey method is used in evidence module's SlashingKeeper interface (expected keeper method).

[julienrbrt]

lgtm!

[atheeshp]

lgtm