Export validator addresses

[michaelfig]

Description

One-liner to export validator addresses properly.

closes: #6528

---

Before we can merge this PR, please make sure that all the following items have been
checked off. If any of the checklist items are not applicable, please leave them but
write a little note why.

• 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

[codecov]

Codecov Report

Merging #6529 into master will increase coverage by 0.03%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #6529      +/-   ##
==========================================
+ Coverage   56.78%   56.81%   +0.03%     
==========================================
  Files         478      478              
  Lines       28745    28746       +1     
==========================================
+ Hits        16322    16333      +11     
+ Misses      11277    11267      -10     
  Partials     1146     1146              

[alexanderbez]

LGTM 🎉

[alessio]

Nihil obstat