Disable quick pick items rather than hiding them when in web environment

[nturinski]

As a workaround, you can use vscode.window.createQuickPick() and then put all this disabled items under a quick pick separator called like "not available"... and then in your qp.onDidAccept handler you could just no-op for those items underneath that separator.

Originally posted by @TylerLeonhardt in microsoft/vscode#179023 (comment)