chore: add additional testcases for fswap (backport #1415)

[mergify]

Description

• add more tests for fswap

Motivation and context

How has this been tested?

Screenshots (if appropriate):

Checklist:

• I followed the contributing guidelines and code of conduct.
• I have added a relevant changelog to CHANGELOG.md
• I have added tests to cover my changes.
• I have updated the documentation accordingly.
• I have updated API documentation client/docs/swagger-ui/swagger.yaml

---

This is an automatic backport of pull request #1415 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of 10726cf has failed:

On branch mergify/bp/release/v0.48.x/pr-1415
Your branch is up to date with 'origin/release/v0.48.x'.

You are currently cherry-picking commit 10726cfaf.
  (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:   x/fswap/types/config_test.go

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	both modified:   CHANGELOG.md
	deleted by us:   x/fswap/keeper/genesis_test.go
	deleted by us:   x/fswap/keeper/grpc_query_test.go
	deleted by us:   x/fswap/keeper/keeper_test.go
	deleted by us:   x/fswap/keeper/msg_server_test.go
	deleted by us:   x/fswap/types/genesis_test.go
	deleted by us:   x/fswap/types/msgs_test.go

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

[jaeseung-bae]

Wrong backport