Dynamic import cors issue and fix not documented

[jankapunkt]

It took me a good bunch of time to find the fix for this and a hint in the docs would be great for others, too.

Background: we tested our app in a few legacy browsers and found this issue to be the cause why the app could not load at all. Fortunately it could be fixed as mentioned at the end of the issue.

I would add the problem description and the fix to the docs. WDYT?

[StorytellerCZ]

I'm for it!