refactor: helper method for register swagger api

[julienrbrt]

Description

Closes: #12149
Superseded #12352
Ran sh scripts/protoc-swagger-gen.sh

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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
• targeted the correct branch (see PR Targeting)
• 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
• reviewed "Files changed" and left comments if necessary
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Reviewers Checklist

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I have...

• confirmed the correct type prefix in the PR title
• confirmed ! in the type prefix if API or client breaking change
• 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 #12955 (42f4fe3) into main (4fe7797) will decrease coverage by 0.33%.
The diff coverage is 55.84%.

@@            Coverage Diff             @@
##             main   #12955      +/-   ##
==========================================
- Coverage   55.87%   55.54%   -0.34%     
==========================================
  Files         646      647       +1     
  Lines       54895    54895              
==========================================
- Hits        30675    30491     -184     
- Misses      21762    21940     +178     
- Partials     2458     2464       +6     

Impacted Files	Coverage Δ
server/swagger.go	0.00% <0.00%> (ø)
simapp/app.go	82.66% <0.00%> (+3.55%)	⬆️
x/distribution/keeper/params.go	75.00% <ø> (-3.58%)	⬇️
x/distribution/module.go	64.28% <ø> (ø)
store/cachekv/store.go	86.61% <45.45%> (+7.49%)	⬆️
types/dec_coin.go	98.41% <50.00%> (-0.79%)	⬇️
snapshots/manager.go	56.91% <57.14%> (+9.32%)	⬆️
crypto/keyring/keyring.go	61.95% <100.00%> (ø)
types/events.go	84.65% <100.00%> (+0.35%)	⬆️
x/distribution/abci.go	76.92% <100.00%> (-23.08%)	⬇️
... and 22 more