chore: fix 0 kwei bug

[whitemoshui]

Description

#7339

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• I have selected the correct base branch.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have made corresponding changes to the documentation.
• My changes generate no new warnings.
• Any dependent changes have been merged and published in downstream modules.
• I ran npm run lint with success and extended the tests and types if necessary.
• I ran npm run test:unit with success.
• I ran npm run test:coverage and my test cases cover all the lines and branches of the added code.
• I ran npm run build and tested dist/web3.min.js in a browser.
• I have tested my code on the live network.
• I have checked the Deploy Preview and it looks correct.
• I have updated the CHANGELOG.md file in the root folder.
• I have linked Issue(s) with this PR in "Linked Issues" menu.

[krzysu]

Looks good! Thanks for your contribution. Let's wait for one more review before merging this.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.51%. Comparing base (1b367e6) to head (7a882b9).

Additional details and impacted files

@@           Coverage Diff           @@
##              4.x    #7387   +/-   ##
=======================================
  Coverage   94.51%   94.51%           
=======================================
  Files         218      218           
  Lines        8557     8557           
  Branches     2363     2364    +1     
=======================================
  Hits         8088     8088           
  Misses        469      469           

Flag	Coverage Δ
UnitTests	94.51% <100.00%> (ø)

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