fixed CPoolSwap not to use bigint to parse

[fuxingloh]

What kind of PR is this?:

/kind fix

What this PR does / why we need it:

fixed CPoolSwap not to use bigint to parse due to platform issues

[github-actions]

size-limit report 📦

Path	Size	Loading time (3g)	Running time (snapdragon)	Total time
packages/jellyfish/dist/jellyfish.umd.js	18.51 KB (0%)	371 ms (0%)	176 ms (+4.82% 🔺)	546 ms

[codecov]

Codecov Report

Merging #169 (0a252b9) into main (4569f64) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main     #169   +/-   ##
=======================================
  Coverage   95.40%   95.40%           
=======================================
  Files          52       52           
  Lines        1111     1111           
  Branches      136      136           
=======================================
  Hits         1060     1060           
  Misses         49       49           
  Partials        2        2           

Impacted Files	Coverage Δ
...jellyfish-transaction/src/script/defi/dftx_pool.ts	100.00% <100.00%> (ø)

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