Add a workaround for browser bug

[alexdima]

The browser is incorrectly sending 2 focus events

Ref #12384

[aiday-mar]

I have been testing this PR and I noticed that it fails on the CSS smoke test. I was able to reproduce this on a real life example. The issue is as follows:

• Reload the code OSS window
• Open the JSON user settings
• Click on the right arrow (the arrow does not move)

This happens because the textInputFocus context key is set to false even though the focus is inside of the editor. The reason it is false, is because it is not correctly updated when the editor looses focus and gains it again. Normally the sequence is as follows:

onFocusChange after focus ->
isFocused from edit context is true

onFocusChange after blur ->
isFocused from edit context is false

In our case, there is a discrepancy between the two states. We can not trust that the focus tracker in the codeEditorWidget.ts file correctly reflects the focus change state on the edit context. We have instead the following sequence.

onFocusChange after focus ->
isFocused from edit context is false

onFocusChange after blur ->
isFocused from edit context is true

In other words there is a discrepancy between the focus state stored inside of the CodeEditorWidgetFocusTracker and the focus state stored inside of the view.ts file.

[aiday-mar]

After some more investigation, it would seem that the bug happens when the CodeEditorWidget detects there is a focus event and the native edit context is focused. It asks for the focus state directly from the NativeEditContext, and the latter replies that it is not focused, even though it is. A fix can be to refresh the focus state on asking for the focus state. This would be a minimal fix.