chore: remove duplicate build script

[snitin315]

What kind of change does this PR introduce?
chore

Did you add tests for your changes?
No
If relevant, did you update the documentation?
No
Summary

remove duplicate build script

Does this PR introduce a breaking change?
No

Other information
No

[codecov]

Codecov Report

Merging #2318 (a625bfa) into master (e44e855) will increase coverage by 19.35%.
The diff coverage is 0.00%.

@@             Coverage Diff             @@
##           master    #2318       +/-   ##
===========================================
+ Coverage   67.45%   86.80%   +19.35%     
===========================================
  Files          63       15       -48     
  Lines        2483      978     -1505     
  Branches      572      267      -305     
===========================================
- Hits         1675      849      -826     
+ Misses        808      129      -679     

Impacted Files	Coverage Δ
packages/webpack-cli/bin/cli.js	55.00% <0.00%> (ø)
packages/webpack-cli/lib/index.js	87.40% <0.00%> (-12.60%)	⬇️
packages/utils/src/copy-utils.ts
packages/generators/src/utils/languageSupport.ts
packages/migrate/src/loaders/loaders.ts
packages/generators/src/utils/styleSupport.ts
packages/utils/src/scaffold.ts
packages/migrate/src/resolve/resolve.ts
packages/utils/src/ast-utils.ts
...ate/src/loaderOptionsPlugin/loaderOptionsPlugin.ts
... and 40 more

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[alexander-akait]

Something wrong with coverage 😕 But not related to this PR

[snitin315]

Hmm, need to look into it.

[alexander-akait]

I think we run it twice, so coverage was wrong

[alexander-akait]

Let's merge

[rishabh3112]

This PR should not have been merged.

Something wrong with coverage confused But not related to this PR

Yup, we are not creating sourcemaps after this PR, which is required for testing ts files.