[webpack] Fix incorrect module overwrite

[jeffersoncasimir]

Closes #9646

Testing instructions:

• Before pulling, experience the bug by doing the following:
• Have a ./project/webpack-project.config.js file that exports nothing. entry = {}; -- It doesn't have to be empty, but make sure you're not overriding the module in the step below
• Delete any module's js/* files; I used login.
• npm run compile -- The js/* files will not get created.

After pulling, everything should compile as normal.

[racostas]

LGTM.
Woks as expected.