Adjust the way LSP finds user's files

[infomiho]

After we introduced bundling of our server code (https://github.com/wasp-lang/wasp/pull/1714), now we have an issue with a different behaviour in our LSP and what our code will tolerate.

Bundler will tolerate "folder imports" while LSP resolves modules differently and won't tolerate "folder imports".

LSP doesn't recognise imports from folders, BUT this will run fine though

Adding index helps (this will also run fine)