fix(styles-loader): hash css module classes from files in node_modules

[zacowan]

Description

• Updates the logic in the prod bundler to hash class names from css modules located in node_modules.
• Migrates the above production-specific logic into both the dev and the prod bundler.
• Applies the same logic in the server bundler.

Motivation

There are two core issues here: deviation from the spec of css modules, and inconsistent behavior between the dev and prod bundler.

When a css file ends in .module.css, this is an indication from the writer of the css that the classes within it should definitely be hashed. In #124, a change was introduced (specifically in the production bundler) that caused any css files imported from within node_modules to not be hashed. Since this change makes no distinction between files ending in .css and .module.css, any css file (including css modules) will result in classes not being hashed.

Additionally, since #124 was introduced this change was not carried over into the dev bundler. This meant that your application would result in different classes depending on which bundler was being used.

Test Conditions

• Added unit tests for ensuring classes from css modules are hashed

Types of changes

Check boxes that apply:

• 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)
• Documentation (adding or updating documentation)
• Dependency update
• Security update

Checklist

• My code follows the code style of this project.
• My change requires a change to the documentation and I have updated the documentation accordingly.
• These changes should be applied to a maintenance branch.
• I have added the Apache 2.0 license header to any new files created.