GH-9262: Fixed the double hover issue for the currentFrame editor

[kittaakos]

What it does

• This PR disables the default editor-contribution hover (such has textdocument/hover for JS/TS) from monaco for the currentFrame editor.
• Fixes the string, number, and boolean coloring in the debug hover and the Variables view.
• This PR makes the debug hover content hidden when the expression is not complex (!expression.hasChildren).

Closes #9262

How to test

const x = 'alma';
const y = 36;
const z = true;
const complex = {
    foo: 'bar'
};
const large = {
    ...complex,
    'some string': 1
};

console.log(x, y, z, complex, large);

• Test with the snippet.
• Before the debug session, verify that you can see the default editor hover.
• Start a debug session, check that the default hover is not there. (Please also check the color of the variables),
• Stop the debug session, the default hover is available again.
• Verify the colors in the Variables view.

screencast.2021-03-29.10-53-07.mp4

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

[kittaakos]

@colin-grant-work, @marechal-p, I have made the changes based on your feedback. Could you please continue with the review. Thanks!

[paul-marechal]

Code LGTM, I verified that hovering is only showing either debug or LS info depending on the debugging state, and that colors are better.

[kittaakos]

Thank you!