refactor: split ExportGenesis into two functions to maintain backwards compatibility

[julienrbrt]

Description

Upstream osmosis-labs#339

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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
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• provided a link to the relevant issue or specification
• followed the guidelines for building modules
• included the necessary unit and integration tests
• added a changelog entry to CHANGELOG.md
• included comments for documenting Go code
• updated the relevant documentation or specification
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Reviewers Checklist

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I have...

• confirmed the correct type prefix in the PR title
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• 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]

Codecov Report

Merging #13448 (f144b72) into main (92394f2) will decrease coverage by 0.02%.
The diff coverage is 100.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #13448      +/-   ##
==========================================
- Coverage   53.87%   53.85%   -0.03%     
==========================================
  Files         651      651              
  Lines       56386    56388       +2     
==========================================
- Hits        30380    30365      -15     
- Misses      23578    23596      +18     
+ Partials     2428     2427       -1     

Impacted Files	Coverage Δ
simapp/export.go	11.94% <100.00%> (ø)
types/module/module.go	66.25% <100.00%> (+0.28%)	⬆️
x/distribution/simulation/operations.go	80.64% <0.00%> (-9.68%)	⬇️
crypto/keys/internal/ecdsa/privkey.go	83.01% <0.00%> (+1.88%)	⬆️