fix: leverage gov proposal migrations

[robert-zaremba]

Description

closes: #1627

---

Author Checklist

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I have...

• included the correct type prefix in the PR title
• added ! to the type prefix if API or client breaking change
• added appropriate labels to the PR
• targeted the correct branch (see PR Targeting)
• provided a link to the relevant issue or specification
• added a changelog entry to CHANGELOG.md
• included comments for documenting Go code
• updated the relevant documentation or specification
• reviewed "Files changed" and left comments if necessary
• confirmed all CI checks have passed

Reviewers Checklist

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I have...

• confirmed the correct type prefix in the PR title
• confirmed all author checklist items have been addressed
• reviewed state machine logic
• reviewed API design and naming
• reviewed documentation is accurate
• reviewed tests and test coverage
• manually tested (if applicable)

[codecov-commenter]

Codecov Report

Merging #1640 (94d8876) into main (7e9ab7a) will increase coverage by 0.05%.
The diff coverage is 66.27%.

@@            Coverage Diff             @@
##             main    #1640      +/-   ##
==========================================
+ Coverage   54.05%   54.11%   +0.05%     
==========================================
  Files          71       72       +1     
  Lines        7150     7200      +50     
==========================================
+ Hits         3865     3896      +31     
- Misses       2988     3004      +16     
- Partials      297      300       +3     

Impacted Files	Coverage Δ
x/leverage/keeper/limits.go	13.88% <0.00%> (-1.74%)	⬇️
x/leverage/types/codec.go	41.17% <0.00%> (-7.10%)	⬇️
x/leverage/types/msgs.go	6.34% <ø> (+1.73%)	⬆️
x/leverage/types/proposal.go	33.33% <33.33%> (ø)
x/leverage/keeper/keeper.go	66.41% <50.00%> (ø)
x/leverage/keeper/oracle.go	64.13% <71.42%> (+1.05%)	⬆️
x/leverage/keeper/liquidate.go	84.00% <86.66%> (+0.96%)	⬆️
x/leverage/client/tests/tests.go	100.00% <100.00%> (ø)
x/leverage/keeper/grpc_query.go	62.68% <100.00%> (ø)
... and 2 more

[toteki]

lint: don't use an underscore in package name (upgrade3_3)

[toteki]

Once the package name lint is resolved, this looks good. How extensive was our local testing?