[BUGFIX]: add lowercase alias ext:<extensionname> for SCSS imports

[luisbecker-gh]

@import/@use Statements in SCSS do no work with the "EXT:" Syntax but with "@" it worked just fine. I discovered, that the SCSS resolve function always gets the import filepath as lowercase string.
Example:
@import "EXT:sitepackage" would match a alias like ext:sitepackage but not the existing alias EXT:sitepackage

This commit adds an additional alias with the lowercase ext:, so SCSS can resolve the files correctly.

Could you please verify my results and are there any concerns about extending the aliases that way?

Thank you!

I tested with:
npm packages:
vite@8.0.13
vite-plugin-typo3@3.0.0
sass-embedded@1.99.0

TYPO3:
TYPO3 13.3.33
praetorius/vite-asset-collector 1.18.1

Fixes: #19

[s2b]

I haven't tested it myself, but your approach sounds reasonable. Could you adjust the unit tests to get the pipeline green? I'll probably add a integration test after that to verify the sass behavior (you can of course also tackle this, feel free to contact me for help)

[luisbecker-gh]

The unit tests are fixed, I also had a go at the integration test. I had to add sass as dev-dependency. Let me know if you want it to be a seperate test instead.