migration slashing data

[skyargos]

Closes: #XXX
Related: #XXX

Description

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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

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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]"

[codecov]

Codecov Report

Merging #743 (02e4c63) into shentu-prefix (725de9b) will decrease coverage by 0.21%.
The diff coverage is 0.00%.

Additional details and impacted files

@@                Coverage Diff                @@
##           shentu-prefix     #743      +/-   ##
=================================================
- Coverage          46.54%   46.33%   -0.21%     
=================================================
  Files                126      126              
  Lines              11905    11958      +53     
=================================================
  Hits                5541     5541              
- Misses              5871     5924      +53     
  Partials             493      493              

Files Changed	Coverage Δ
app/upgrade_handler.go	5.55% <0.00%> (-15.50%)	⬇️

[skyargos]

Moved to upgrade_handler processing