Fix x/genutil ExportGenesis

[alexanderbez]

Closes: #5765

Description

Fix x/genutil ExportGenesis as to not return null, but instead default genesis state ([]), so on export, genesis validation should pass.

---

For contributor use:

• Targeted PR against correct branch (see CONTRIBUTING.md)
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Code follows the module structure standards.
• Wrote unit and integration tests
• Updated relevant documentation (docs/) or specification (x/<module>/spec/)
• Added relevant godoc comments.
• Added a relevant changelog entry to the Unreleased section in CHANGELOG.md
• Re-reviewed Files changed in the Github PR explorer

---

For admin use:

• Added appropriate labels to PR (ex. WIP, R4R, docs, etc)
• Reviewers assigned
• Squashed all commits, uses message "Merge pull request #XYZ: [title]" (coding standards)

[toml01]

Shouldn't ExportGenesis return the list of GenTxs if exists, instead of the default state?

[alexanderbez]

No, since this is for exporting state. In other words, we already have initiated and bootstrapped the chain, so we don't need genesis txs to do so.

[codecov]

Codecov Report

Merging #5775 into master will not change coverage.
The diff coverage is 0%.

@@           Coverage Diff           @@
##           master    #5775   +/-   ##
=======================================
  Coverage   35.91%   35.91%           
=======================================
  Files         341      341           
  Lines       34745    34745           
=======================================
  Hits        12478    12478           
  Misses      21023    21023           
  Partials     1244     1244

Impacted Files	Coverage Δ
x/genutil/module.go	0% <0%> (ø)	⬆️