Fix localization import order

[msujew]

What it does

Closes #12977

Fixes two localization based issues, see the first two commits for more info. The issue came from the fact that we now import a bit more code during our preload script and accidentally imported code that was supposed to be translated during its import time - effectively removing the ability to translate those files.

The same thing happened for monaco, where we import code from @theia/monaco-editor-core before being able to localize the monaco texts. This code has been moved to the correct package.

How to test

1. Open Theia (Electron) and change the locale
2. Assert that common commands and monaco commands are localized

Review checklist

• As an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• As a reviewer, I agree to behave in accordance with the review guidelines

[planger]

Thank you, this change looks fine to me!

I can confirm that on master several translations don't work in a Theia Electron app anymore and with this change they work again just fine. 👍 Also, the move of the language registration to the Monaco extension makes more sense now in general.

Thank you for this fix @msujew!