fix: respect negatedDescription for flags from schema

[snitin315]

What kind of change does this PR introduce?
bugfix

Did you add tests for your changes?
No

If relevant, did you update the documentation?
No
Summary

For webpack/webpack-dev-server#4216

Does this PR introduce a breaking change?
No

Other information
Internal usage.

[codecov]

Codecov Report

Merging #3102 (9ae7efc) into master (4650e66) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #3102   +/-   ##
=======================================
  Coverage   93.56%   93.57%           
=======================================
  Files          22       22           
  Lines        1617     1618    +1     
  Branches      484      483    -1     
=======================================
+ Hits         1513     1514    +1     
  Misses        104      104           

Impacted Files	Coverage Δ
packages/webpack-cli/lib/webpack-cli.js	93.92% <100.00%> (+<0.01%)	⬆️

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[alexander-akait]

@snitin315 Feel free to ping me when it will be green and merged, I will do relesae

[snitin315]

@alexander-akait done

[dmvol81]

What kind of change does this PR introduce?

bugfix

Did you add tests for your changes?

No

If relevant, did you update the documentation?

No

Summary

For webpack/webpack-dev-server#4216

Does this PR introduce a breaking change?

No

Other information

Internal usage.