Problem: no MaxTx set from config for mempool

[mmsqe]

Closes: #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]" (coding standards)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 61.59%. Comparing base (f9cd15e) to head (cd50490).

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #496      +/-   ##
===========================================
+ Coverage    61.57%   61.59%   +0.01%     
===========================================
  Files          128      128              
  Lines         9474     9477       +3     
===========================================
+ Hits          5834     5837       +3     
  Misses        3100     3100              
  Partials       540      540              

Files	Coverage Δ
app/app.go	76.42% <100.00%> (+0.12%)	⬆️
server/config/config.go	35.44% <ø> (ø)