Change the logic to determine if the pool was depleted

[hallazzang]

Description

closes: #364

---

Before we can merge this PR, please make sure that all the following items have been
checked off. If any of the checklist items are not applicable, please leave them but
write a little note why.

• 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
• Review Codecov Report in the comment section below once CI passes

[codecov]

Codecov Report

Merging #369 (096a0a0) into develop (d1c90aa) will increase coverage by 0.03%.
The diff coverage is 82.60%.

@@             Coverage Diff             @@
##           develop     #369      +/-   ##
===========================================
+ Coverage    83.01%   83.05%   +0.03%     
===========================================
  Files           20       20              
  Lines         2249     2254       +5     
===========================================
+ Hits          1867     1872       +5     
  Misses         209      209              
  Partials       173      173              

Impacted Files	Coverage Δ
x/liquidity/keeper/liquidity_pool.go	79.59% <80.95%> (+0.15%)	⬆️
x/liquidity/keeper/swap.go	81.53% <100.00%> (+0.28%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update d1c90aa...096a0a0. Read the comment docs.

[dongsam]

@hallazzang

Could you revert the changes about QuoTruncate, MulTruncate?
I think it should be fixed separately after decided on #380

and I'd appreciate it if you could resolve the conflict.

[hallazzang]

@dongsam It has changed, please check it again.