Handle languageclient errors cases more robustly

[kaisalmen]

I moved some tests around (wrong places) as well.
Fixing the wrapper handling in case of error introduced required changes to the react component and to several tests.

After thinking about #855

[kaisalmen]

@CGNonofr I finally understood why awaiting the language client on connection error broke the await in the test and it is now fixed with: 8c2b8f8

In a real application you should always define your own error handler!

[kaisalmen]

@CGNonofr last commit is for the problem @cdietrich discovered with the react component introduced by 6.3.0 version. We now have 78 unit tests.

[CGNonofr]

not easy to review! 😢 LGTM though

[kaisalmen]

@CGNonofr sorry, once I started fixing the tests the domino effect started.

[CGNonofr]

@CGNonofr sorry, once I started fixing the tests the domino effect started.

As always, same for me 😆

[kaisalmen]

@CGNonofr These changes made the Unknown Error: ResizeObserver loop completed with undelivered notifications. in the tests go away. The question now is why exactly, but if we find an answer this could be interesting. The monaco-vscode-api version was unchanged, btw.