Wrong webpack cfg condition: sourceMap: isEnvProduction && shouldUseSourceMap

[mixalbl4-127]

Describe the bug

Here: https://github.com/facebook/create-react-app/blob/master/packages/react-scripts/config/webpack.config.js
wrong condition: sourceMap: isEnvProduction && shouldUseSourceMap
correct condition: sourceMap: isEnvDevelopment && shouldUseSourceMap

Why?
SourceMaps needs in Dev mode, in Prod it must be always disabled. But this condition enable Style Source Maps ONLY in PROD + shouldUseSourceMap, in all other situations it will be False

Research results:

1. this issue because of this bug

[heyimalex]

We intentionally only make sourcemaps for production builds for various reasons, but that issue should be looked at again.