feat: decouple x/distribution from simapp

[julienrbrt]

Description

Implements the remaining two tasks of #12292
Closes: #12292

---

Author Checklist

All items are required. Please add a note to the item if the item is not applicable and
please add links to any relevant follow up issues.

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
• confirmed all CI checks have passed

Reviewers Checklist

All items are required. Please add a note if the item is not applicable and please add
your handle next to the items reviewed if you only reviewed selected items.

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 #12334 (da161eb) into main (6559c7a) will decrease coverage by 0.21%.
The diff coverage is 97.14%.

❗ Current head da161eb differs from pull request most recent head 48550a9. Consider uploading reports for the commit 48550a9 to get more accurate results

@@            Coverage Diff             @@
##             main   #12334      +/-   ##
==========================================
- Coverage   66.15%   65.93%   -0.22%     
==========================================
  Files         676      676              
  Lines       71315    71295      -20     
==========================================
- Hits        47177    47009     -168     
- Misses      21493    21648     +155     
+ Partials     2645     2638       -7     

Impacted Files	Coverage Δ
simapp/test_helpers.go	16.45% <ø> (+1.72%)	⬆️
x/distribution/simulation/operations.go	80.74% <94.73%> (-9.47%)	⬇️
x/distribution/client/testutil/grpc_query_suite.go	99.26% <100.00%> (ø)
x/distribution/client/testutil/suite.go	96.43% <100.00%> (-2.38%)	⬇️
...distribution/client/testutil/withdraw_all_suite.go	100.00% <100.00%> (ø)
x/distribution/simulation/proposals.go	77.77% <100.00%> (ø)
x/gov/simulation/proposals.go	100.00% <100.00%> (ø)
x/mint/abci.go	0.00% <0.00%> (-88.89%)	⬇️
x/distribution/keeper/invariants.go	0.00% <0.00%> (-75.00%)	⬇️
x/distribution/module.go	54.11% <0.00%> (-15.30%)	⬇️
... and 6 more