fix: export x/collection params into genesis (backport #1268)

[mergify]

Description

x/collection does not export its params into genesis. This patch addresses the problem.

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 #1268 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of e86b980 has failed:

On branch mergify/bp/release/v0.48.x/pr-1268
Your branch is up to date with 'origin/release/v0.48.x'.

You are currently cherry-picking commit e86b98002.
  (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:   x/collection/keeper/genesis.go
	modified:   x/collection/keeper/genesis_test.go

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   CHANGELOG.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

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 69.78%. Comparing base (8b312a6) to head (7a9670c).

Additional details and impacted files

@@                 Coverage Diff                 @@
##           release/v0.48.x    #1290      +/-   ##
===================================================
- Coverage            69.78%   69.78%   -0.01%     
===================================================
  Files                  646      646              
  Lines                67506    67507       +1     
===================================================
  Hits                 47108    47108              
- Misses               18212    18213       +1     
  Partials              2186     2186              

Files	Coverage Δ
x/collection/keeper/genesis.go	96.00% <100.00%> (+0.01%)	⬆️

... and 1 file with indirect coverage changes