Respect included property on preferences

[msujew]

What it does

Closes #11587. Preferences that should not be included (i.e. included: false) are ignored when building the preference schema.

How to test

1. Start the application on Mac (or set one of the preferences included properties to false)
2. Assert that the preference is not rendered/does not appear in the search of the preference widget
3. Assert that the preference cannot be accessed using the settings text editor

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

[vince-fugnitto]

@msujew I confirmed that the preference is hidden from the UI but I believe we need more.
The preference still exists as a suggestion in the settings.json and setting the preference still takes effect which can cause unwanted side effects.

In my example I also set workbench.statusBar.visible to include: false and it still shows up, and takes effect:

[msujew]

@vince-fugnitto Right, I'll look into that 👍

[colin-grant-work]

This is the correct approach - preventing the preference from ever being registered with the schema at all. In testing, this prevents undesired / inapplicable preferences from appearing in any context. 👍

[vince-fugnitto]

@msujew should we still go ahead with #11584 after your changes?

[vince-fugnitto]

The changes unfortunately include a regression in the browser application on macOS where the top-level disappears after the application is loaded. I'll need to see why that happens:

[colin-grant-work]

        'window.menuBarVisibility': {
            type: 'string',
            enum: ['classic', 'visible', 'hidden', 'compact'],
            markdownEnumDescriptions: [
                nls.localizeByDefault('Menu is only hidden in full screen mode.'),
                nls.localizeByDefault('Menu is always visible even in full screen mode.'),
                nls.localizeByDefault('Menu is always hidden.'),
                nls.localizeByDefault('Menu is displayed as a compact button in the sidebar. This value is ignored when `#window.titleBarStyle#` is `native`.')
            ],
            default: 'classic',
            scope: 'application',
            // eslint-disable-next-line max-len
            markdownDescription: nls.localizeByDefault("Control the visibility of the menu bar. A setting of 'toggle' means that the menu bar is hidden and a single press of the Alt key will show it. By default, the menu bar will be visible, unless the window is full screen."),
            included: !isOSX
        },

The included should check whether we're in Electron or not. If we're in the browser, the preference should be present, even on MacOS.