BUG: add shield crisis invariant fix for the upgrade

[yoongbok-lee]

Closes: # Related: #XXX

Description

To test the invariant being broken,

first start with a v2.2.0 binary.

1. Deposit collateral to shield
2. Create a pool
3. update the pool, with some additional native fees
4. upgrade to v2.3.0 and v2.4.0, and finally latest master
5. There will be 3 consecutive upgrades
6. The chain will halt at the last upgrade since the crisis invariant is broken due to the bug that happened in the original v2.2.0 binary.

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• [ ] Code follows the module structure standards.
• [ ] Wrote unit and integration tests
• [ ] Updated relevant documentation (docs/) or specification (x/<module>/spec/)
• [ ] Added relevant godoc comments.
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[yoongbok-lee]

This is currently blocked due to the shield mixedcoins removal missing a upgrade store migration.

[yoongbok-lee]

Since shield will have its own migration I think it's better to do this there.

[codecov[bot]]

Codecov Report

Merging #471 (346d607) into master (7b4fa10) will decrease coverage by 0.19%. The diff coverage is 2.56%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #471      +/-   ##
==========================================
- Coverage   41.52%   41.33%   -0.20%     
==========================================
  Files         124      124              
  Lines       11421    11476      +55     
==========================================
+ Hits         4743     4744       +1     
- Misses       6219     6273      +54     
  Partials      459      459              

Impacted Files	Coverage Δ
app/upgrade_handler.go	3.14% <0.00%> (-2.33%)	:arrow_down:
app/app.go	86.92% <100.00%> (+0.02%)	:arrow_up: