refactor: mempool: remove unused totalCheckTxCount

[arajasek]

Describe your changes and provide context

Drops the unused totalCheckTxCount counter from the mempool. This metric tracks the total number of transactions that the mempool asks the app to check.

The figure isn't ever read, and I can't really think of a reason why we might ever want to use it, so I propose dropping it.

Testing performed to validate your change

make test succeeds.

[github-actions]

The latest Buf updates on your PR. Results from workflow Buf / buf (pull_request).

Build	Format	Lint	Breaking	Updated (UTC)
✅ passed	✅ passed	✅ passed	✅ passed	Dec 12, 2025, 10:41 PM

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 43.24%. Comparing base (3bfc150) to head (cf05171).
⚠️ Report is 1 commits behind head on main.

❌ Your project status has failed because the head coverage (38.27%) is below the target coverage (40.00%). You can increase the head coverage or adjust the target coverage.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2589      +/-   ##
==========================================
+ Coverage   42.04%   43.24%   +1.20%     
==========================================
  Files        1512     1851     +339     
  Lines      119181   152771   +33590     
==========================================
+ Hits        50107    66073   +15966     
- Misses      64729    80825   +16096     
- Partials     4345     5873    +1528     

Flag	Coverage Δ
sei-chain	42.08% <ø> (+0.02%)	⬆️
sei-cosmos	38.03% <ø> (-0.02%)	⬇️
sei-db	69.06% <ø> (ø)
sei-ibc-go	55.96% <ø> (ø)
sei-tendermint	47.51% <ø> (?)
sei-wasmd	42.11% <ø> (ø)
sei-wasmvm	39.88% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
sei-tendermint/internal/mempool/mempool.go	67.73% <ø> (ø)

... and 346 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[udpatil]

LGTM, doesn't seem to be used in any alerting or common grafana dashboards