imp(core): allow huckleberry events with a prefix (backport #5541)

[mergify]

This is an automatic backport of pull request #5541 done by Mergify.
Cherry-pick of 2375109 has failed:

On branch mergify/bp/release/v7.3.x/pr-5541
Your branch is up to date with 'origin/release/v7.3.x'.

You are currently cherry-picking commit 2375109a.
  (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:
	new file:   modules/core/keeper/events_test.go
	new file:   modules/core/keeper/export_test.go
	new file:   modules/core/types/events.go
	new file:   testing/mock/events.go
	modified:   testing/mock/ibc_module.go

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   modules/core/keeper/msg_server.go
	both modified:   modules/core/keeper/msg_server_test.go

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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[srdtrk]

Also going to remove link checker in this PR